Refrigerator and control method thereof

ABSTRACT

A refrigerator includes a cabinet forming a storage space, a main door that opens and closes the storage space while defining an opening part that is in communication with the storage space, a sub-door mounted to the main door and configured to open and close the opening part, the sub-door including a panel assembly for allowing selective viewing of an inside of the opening part, the injection port is provided at a lower side of the sub-door to direct an insulating foaming solution to a space in the sub-door, a detection device for detecting an operation of a user, a lighting unit inside the refrigerator that turns on based on user operation to allow selective viewing of the inner side of the opening part, and a display unit inside the refrigerator at a position corresponding to the panel.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.16/784,689, filed on Feb. 7, 2020, which is a continuation of U.S.application Ser. No. 16/146,522, filed Sep. 28, 2018, now U.S. Pat. No.10,598,427, which is a continuation of U.S. application Ser. No.15/399,161, filed Jan. 5, 2017, now U.S. Pat. No. 10,119,751, whichclaims priority under 35 U.S.C. § 119 and 35 U.S.C. § 365 to KoreanPatent Application No. 10-2016-0001292, filed in Korea on Jan. 5, 2016,whose entire disclosures are hereby incorporated by reference.

FIELD

The present disclosure is related to a refrigerator and a control methodthereof.

BACKGROUND

Generally, a refrigerator is a home appliance which stores food at a lowtemperature in a storage space formed therein to be shielded by a door.To this end, the refrigerator may be formed to cool an inside of thestorage space using cooling air generated through heat exchange with arefrigerant circulated in a refrigeration cycle, and thus to keep thestored food in an optimum state.

Recent refrigerators have tended to become bigger and possessmulti-functions based on changes in diet and a tendency towardhigh-quality products. Also, refrigerators having various structures anddevices for improved convenience use of internal spaces have beenreleased.

The storage space of the refrigerator may be opened and closed by thedoor. The refrigerator may be classified into various types according toan arrangement of the storage space and a structure of the door foropening and closing the storage space.

In some cases, a separate accommodation space which allows access froman outside may be provided at the door of the refrigerator. Thus, accessto the accommodation space may be allowed by opening an auxiliary dooror a home-bar door without opening of the entire refrigerator door.

Therefore, food that is frequently used may be accommodated in theseparate accommodation space provided at the refrigerator door. Andsince the entire refrigerator door is not opened to accommodate thefood, leaking of the cooling air in the refrigerator may be minimized.

However, even in such a structure, the food inside the refrigerator maynot be checked without opening the refrigerator door. That is, to checkwhether desired food is accommodated in the space inside refrigerator orin the separate accommodation space provided at the door, the doorshould be opened. If the desired food is not found when the auxiliarydoor or the home-bar door is opened, the main door may then need to beopened, thus leading to an unnecessary leaking of the cooling air.

BRIEF DESCRIPTION OF THE DRAWINGS

Implementations will be described in detail with reference to thefollowing drawings in which like reference numerals refer to likeelements, and wherein:

FIG. 1 is a perspective view of an example refrigerator;

FIG. 2 is a front view illustrating a state in which all doors of therefrigerator are opened;

FIG. 3 is a perspective view illustrating a state in which a sub-door ofthe refrigerator is opened;

FIG. 4 is a front view illustrating a state in which the sub-door isopaque;

FIG. 5 is a front view illustrating a state in which the sub-door istransparent;

FIG. 6 is a perspective view illustrating a state in which a main doorand the sub-door of the refrigerator are coupled to each other;

FIG. 7 is an exploded perspective view illustrating a state in which themain door and the sub-door are separated;

FIG. 8 is an exploded perspective view of the main door;

FIG. 9 is an exploded perspective view of the main door and a displayunit;

FIGS. 10A and 10B are partial perspective views illustrating aninstalling state of the display unit;

FIG. 11 is a cross-sectional view illustrating an installed state of thedisplay unit;

FIG. 12 is an exploded perspective view of an example display assembly;

FIG. 13 is a cross-sectional view taken along line 13-13′ of FIG. 1 ;

FIG. 14 is an exploded perspective view of an example installationstructure of a door opening device;

FIG. 15 is a view illustrating an operation state of the door openingdevice;

FIG. 16 is a cross-sectional view taken along line 16-16′ of FIG. 1 ;

FIG. 17 is a perspective view of the sub-door;

FIG. 18 is an exploded perspective view of the sub-door when seen fromthe front;

FIG. 19 is an exploded perspective view of the sub-door when being seenfrom the rear;

FIG. 20 is a cut-away perspective view taken along line 20-20′ of FIG.17 ;

FIG. 21 is an exploded perspective view of an example panel assembly;

FIG. 22 is a cross-sectional view schematically illustrating an exampleof a front panel of the panel assembly;

FIG. 23 is a cross-sectional view schematically illustrating anotherexample of the front panel of the panel assembly;

FIG. 24 is a cross-sectional view schematically illustrating stillanother example of the front panel of the panel assembly;

FIG. 25 is a cross-sectional view of the sub-door;

FIG. 26 is an exploded perspective view illustrating a couplingstructure of the sub-door and an upper hinge;

FIG. 27 is a partial perspective view illustrating an installed state ofthe upper hinge;

FIG. 28 is a longitudinal cross-sectional view illustrating a couplingstructure of the upper hinge;

FIG. 29 is a longitudinal cross-sectional view illustrating a couplingstructure of the sub-door and a lower hinge;

FIG. 30 is an exploded perspective view illustrating a couplingstructure of a knock detection device and a second detection device ofthe sub-door when being seen from a front;

FIG. 31 is an exploded perspective view illustrating a couplingstructure of the knock detection device and the second detection deviceof the sub-door when being seen from a lower side;

FIG. 32 is an exploded perspective view of the knock detection device;

FIG. 33 is a cross-sectional view taken along line 33-33′ of FIG. 17 ;

FIG. 34 is a cross-sectional view of an example microphone module of theknock detection device;

FIG. 35 is an exploded perspective view illustrating a couplingstructure of the second detection device;

FIG. 36 is a partial perspective view illustrating an installed state ofthe second detection device;

FIG. 37 is a view illustrating an electric wire arrangement inside thesub-door;

FIG. 38 is a perspective view illustrating a state in which a foamingsolution is injected into the sub-door;

FIG. 39 is a view illustrating an arrangement of a vent hole of thesub-door;

FIG. 40 is a perspective view illustrating an operation state of aprojector of the refrigerator;

FIG. 41 is a cut-away perspective view illustrating an internalstructure of a freezer compartment of the refrigerator;

FIG. 42 is a block diagram illustrating a flow of a control signal ofthe refrigerator;

FIG. 43 is a flowchart sequentially illustrating an operation of thesub-door of the refrigerator;

FIG. 44 is a perspective view illustrating an installed state of thedisplay unit;

FIG. 45 is a view illustrating a configuration of a front surface of thedisplay unit;

FIG. 46 is a view illustrating a change in a display state of thedisplay unit according to a knocking operation;

FIG. 47 is a view illustrating the change in the display state when thesub-door is opened and closed;

FIG. 48 is a view illustrating the change in the display state of thedisplay unit when an auto-door function is set;

FIG. 49 is a view illustrating the change in the display state of thedisplay unit when an auto-drawer function is set; and

FIG. 50 is a view illustrating the change in the display state of thedisplay unit when a temperature fixing function is set.

DETAILED DESCRIPTION

Hereinafter, exemplary implementations of the present disclosure will bedescribed in detail with reference to the accompanying drawings.However, The disclosure may, however, be implemented in many differentforms and should not be construed as being limited to theimplementations set forth herein; rather, alternative implementationsincluded in other retrogressive disclosures or falling within the spiritand scope of the present disclosure can easily be derived throughadding, altering, and removing, and will fully convey the concept of thedisclosure to those skilled in the art.

FIG. 1 is a perspective view of a refrigerator according to animplementation of the present disclosure. And FIG. 2 is a front viewillustrating a state in which all doors of the refrigerator are opened.And FIG. 3 is a perspective view illustrating a state in which asub-door of the refrigerator is opened.

As illustrated in the drawings, an external appearance of a refrigerator1 according to an implementation of the present disclosure may be formedby a cabinet 10 which forms a storage space and a door which opens andcloses the storage space.

An inside of the cabinet 10 may be divided up and down by a barrier 11,and a refrigerator compartment 12 may be formed at an upper portion ofthe cabinet 10, and a freezer compartment 13 may be formed at a lowerportion of the cabinet 10.

And various accommodation members 121 such as a shelf, a drawer and abasket may be provided inside the refrigerator compartment 12. Ifnecessary, the accommodation members 121 may be inserted and withdrawnwhile the door is opened, and may accommodate and store food by theinserting and withdrawing. A main lighting unit 85 which illuminates therefrigerator compartment 12 may be provided at the refrigeratorcompartment 12. The main lighting unit 85 may also be disposed at thefreezer compartment 13, and may also be disposed at any positions of aninner wall surface of the refrigerator 1.

A drawer type freezer compartment accommodation member 131 which isinserted and withdrawn may be mainly disposed inside the freezercompartment 13. The freezer compartment accommodation member 131 may beformed to be inserted and withdrawn, interlocking with opening of afreezer compartment door 30. And a first detection device 31 whichdetects a user's body may be provided at a front surface of the freezercompartment door 30. Detailed description of the first detection device31 will be described again below.

The door may include a refrigerator compartment door 20 and the freezercompartment door 30. The refrigerator compartment door 20 serves to openand close an opened front surface of the refrigerator compartment 12 byrotation, and the freezer compartment door 30 serves to open and closean opened front surface of the freezer compartment 13 by rotation. Onepair of refrigerator compartment doors 20 and one pair of freezercompartment doors 30 may be provided left and right to shield therefrigerator compartment 12 and the freezer compartment 13,respectively.

A plurality of door baskets may be provided at the refrigeratorcompartment door 20 and the freezer compartment door 30. The doorbaskets may be provided so as not to interfere with the accommodationmembers 121 and 131 while the refrigerator compartment door 20 and thefreezer compartment door 30 are closed.

The refrigerator compartment door 20 and the freezer compartment door 30may form an entire exterior when being seen from a front. The exteriorof each of the refrigerator compartment door 20 and the freezercompartment door 30 may be formed of a metallic material, and the entirerefrigerator 1 may have a metallic texture. In some cases, a dispenserwhich dispenses water or ice may be provided at the refrigeratorcompartment door 20.

While the implementations described in this application may refer to anexample in which a French type door opening and closing one space byrotating one pair of doors is applied to a bottom freezer typerefrigerator having the freezer compartment provided at a lower sidethereof, the present disclosure may be applied to all types ofrefrigerators having a door.

In some cases, a right one (in FIG. 1 ) of the pair of refrigeratorcompartment doors 20 may be formed to be doubly opened and closed.Specifically, the right refrigerator compartment door 20 may include amain door 40 which may be formed of the metallic material to open andclose the refrigerator compartment 12, and a sub-door 50 which may berotatably disposed inside the main door 40 to open and close an openingof the main door 40.

The main door 40 may be formed to have the same size as that of a leftone (in FIG. 1 ) of the pair of refrigerator compartment doors 20, maybe rotatably installed at the cabinet 10 by a main hinge 401 and amiddle hinge 402, and thus may open and close a part of the refrigeratorcompartment 12.

An opening part 403 may be formed at the main door 40. A door basket 404may be installed at a rear surface of the main door 40 including aninside of the opening part 403. Therefore, a user may have access to thedoor basket 404 through the opening part 403 without opening of the maindoor 40. A size of the opening part 403 may correspond to most of afront surface of the main door 40 except, for example, a part of aperimeter of the main door 40.

The sub-door 50 may be rotatably installed inside the opening part 403,and may open and close the opening part 403. At least a part of thesub-door 50 may be formed of a transparent material like glass.Therefore, access to the opening part 403 can be allowed through openingof the sub-door 50, and even while the sub-door 50 is closed, it canalso be possible to see through the inside of the opening part 403. Thesub-door 50 may be referred to as a see-through door.

In some cases, the glass material forming the sub-door 50 may be formedto be selectively changed into a transparent or opaque state bycontrolling a light transmittance and a reflectivity thereof accordingto a user's operation. Therefore, the glass material can becometransparent so that an inside of the refrigerator 1 is visible, onlywhen the user wants, and otherwise, can be maintained in the opaquestate.

FIG. 4 is a front view illustrating a state in which the sub-door isopaque.

As illustrated in the drawing, when there are not any operations in therefrigerator 1 while all of the main door 40 and the sub-door 50 areclosed, the sub-door 50 may have an opaque black color or may be in astate like a mirror surface. Therefore, the sub-door 50 may not enablean internal space of the sub-door 50, i.e., an accommodation space ofthe main door 40 and an internal space of the refrigerator compartment12 to be visible.

Therefore, the sub-door 50 may be maintained in a state having the blackcolor, and thus may provide a beautiful and simple exterior having amirror-like texture to the refrigerator 1. Also, the exterior mayharmonize with the metallic texture of the main door 40, therefrigerator compartment door 20 and the freezer compartment door 30,and thus may provide a more luxurious appearance.

FIG. 5 is a front view illustrating a state in which the sub-door istransparent.

As illustrated in the drawing, in a state in which all of the main door40 and the sub-door 50 are closed, the sub-door 50 may be madetransparent by a user's certain operation. When the sub-door 50 is inthe transparent state, the accommodation space of the main door 40 andthe internal space of the refrigerator compartment 12 may be visible.Therefore, the user may confirm an accommodation state of food in theaccommodation space of the main door 40 and the internal space of therefrigerator compartment 12 without opening of the main door 40 and thesub-door 50.

Also, when the sub-door 50 is in the transparent state, a display unit60 disposed at a rear of the sub-door 50 may be in a visible state, andan operation state of the refrigerator 1 may be displayed to an outside.

An exemplary operating method and configuration for enabling theaccommodation space of the main door 40 and the internal space of therefrigerator compartment 12 to be visible will be described below indetail.

FIG. 6 is a perspective view illustrating a state in which the main doorand the sub-door of the refrigerator are coupled to each other. And FIG.7 is an exploded perspective view illustrating a state in which the maindoor and the sub-door are separated. And FIG. 8 is an explodedperspective view of the main door.

As illustrated in the drawings, an external appearance of the main door40 may be formed by an outer plate 41 which may be formed of a metallicmaterial, a door liner 42 which is coupled to the outer plate 41, anddoor cap decorations 45 and 46 which are provided at upper and lowerends of the outer plate 41 and the door liner 42.

The outer plate 41 may be formed of a plate-shaped stainless material,and may be formed to be bent and thus to form a part of a front surfaceand a perimeter surface of the main door 40.

The door liner 42 may be injection-molded with a plastic material, andforms the rear surface of the main door 40. And the door liner 42 mayalso be formed so that an area thereof corresponding to the opening part403 is opened. The opening part 403 may have a plurality of unevenstructures so that the door basket 404 is installed.

A rear gasket 44 may be provided at a perimeter of a rear surface of thedoor liner 42. The rear gasket 44 is in close contact with a perimeterof the cabinet 10, and prevents a leak of cooling air between the maindoor 40 and the cabinet 10.

In some cases, a door lighting unit 49 which illuminates the inside ofthe opening part 403 may be provided at an upper surface of the doorliner 42. The door lighting unit 49 may emit light downward from anupper side of the opening part 403, and thus may illuminate the entireopening part 403 including the door basket 404, and may also enable thesub-door 50 to be in the transparent state.

The cap decorations 45 and 46 may form an upper surface and a lowersurface of the main door 40, and a hinge installation part 451 whichenables the main door 40 to be rotatably installed at the cabinet 10 maybe formed at each of the cap decorations 45 and 46. An upper end of themain door 40 may be coupled to the main hinge 401, and a lower end ofthe main door 40 may be coupled to the middle hinge 402, and thus theupper and lower ends of the main door 40 may be rotatably supported.

A door handle 462 may be formed to be recessed from the lower surface ofthe main door 40, i.e., the cap decoration 46. For example, the user mayput a hand into the door handle 462, may rotate the main door 40, andthus may open and close the refrigerator compartment 12.

In some cases, a door frame 43 may be further provided between the outerplate 41 and the door liner 42. The door frame 43 may be coupled betweenthe outer plate 41 and the door liner 42, and may form a perimeter ofthe opening part 403.

In a state in which the outer plate 41, the door liner 42, the doorframe 43, and the cap decorations 45 and 46 are coupled with each other,a foaming solution may be filled inside an internal space of the maindoor 40, and thus an insulation may be formed therein. That is, theinsulation may be disposed at a perimeter area of the opening part 403,and thus isolate a space inside the refrigerator 1 from a space outsidethe refrigerator 1.

The door frame 43 may be injection-molded with a plastic material whichis different from that of the door linier 42. In some cases, the doorframe 43 may be integrally formed with the door liner 42, and may bedirectly coupled to the outer plate 41.

A frame stepped part 431 which protrudes inward may be formed at aninner surface of the door frame 43. Therefore, when the sub-door 50 isclosed, the frame stepped part 431 may support the sub-door 50.

A front gasket 434 may be provided at the frame stepped part 431. Thefront gasket 434 may be in contact with a rear surface of the sub-door50 when the sub-door 50 is closed to thereby provide a seal between themain door 40 and the sub-door 50. Of course, the front gasket 434 may beomitted in some cases. Also, the front gasket 434 may be formed in asheet shape formed of a metallic material, and may also be formed to bein close contact with a sub-door gasket 591 having a magnetic force bythe magnetic force.

A frame heater 4321 may be provided at a rear surface of the framestepped part 431. The frame heater 4321 is disposed along the framestepped part 431, and heats the frame stepped part 431. The framestepped part 431 may have a relatively low surface temperature due to aninfluence of cooling air in the refrigerator 1. Therefore, dewcondensation may occur on a surface of the frame stepped part 431. Thedew condensation may be prevented by driving of the frame heater 4321.

A hinge hole 433 in which each of sub-hinges 51 and 52 for installingthe sub-door 50 is installed may be formed at each of both sides of thedoor frame 43. The hinge hole 433 may be formed at a position whichfaces a side surface of the sub-door 50, and also formed so that each ofthe sub-hinges 51 and 52 is inserted therein.

In some cases, a hinge case 47 may be provided at the inner surface ofthe door frame 43 (which is in contact with the insulation)corresponding to the hinge hole 433. The hinge case 47 may be formed byvertically coupling a first case 471 and a second case 472 to eachother. The hinge case 47 can form a space which rotatably accommodates apart of each of the sub-hinges 51 and 52 inserted through the hinge hole433 when the first case 471 and the second case 472 are coupled to eachother.

A hinge installation member 473 may be provided at a recessed space ofthe hinge case 47. The hinge installation member 473 may be fixed by thecoupling of the first case 471 and the second case 472. The hingeinstallation member 473 may be formed of a steel material, and may havea shaft insertion part 4731 in which a hinge shaft of each of thesub-hinges 51 and 52 is inserted.

The hinge case 47 may be installed at the hinge hole 433 which may beformed at each of upper and lower portions of the door frame 43. And thehinge cases 47 which are disposed up and down may be formed to have thesame structure and shape.

In some cases, a hinge frame 48 may be provided at an outside of thedoor frame 43. The hinge frame 48 may be formed to vertically extend,and fixes the hinge cases 47 which are disposed up and down.

For instance, the hinge frame 48 may be formed of a metallic material ora plastic material having excellent strength, may be formed in a plateshape, and may be formed to vertically extend. An upper end 482 and alower end 483 of the hinge frame 48 may be bent, and then may be coupledand fixed to the cap decorations 45 and 46 provided at the upper andlower ends of the main door 40. That is, the upper end 482 and the lowerend 483 of the hinge frame 48 may be fixed to the cap decorations 45 and46, and thus an installation position thereof may be maintained.Moreover, the hinge frame 48 may indirectly support the sub-hinges 51and 52.

A case fixing part 481 may be formed at each of upper and lower portionsof the hinge frame 48. The case fixing part 481 may be formed by cuttingaway a part of the hinge frame 48. Therefore, a portion of the hingecase 47 which forms the recessed space may be accommodated and fixedinto the cut-away case fixing part 481 of the hinge frame 48. The hingecase 47 may be coupled to the hinge frame 48 by a separate fasteningmember such as a screw.

A frame reinforcing part 484 may be formed between the case fixing parts481, which are formed at the upper and lower portions of the hinge frame48, to be recessed. And a plurality of frame openings 485 may be formedat the frame reinforcing part 484. The frame reinforcing part 484 mayreinforce strength of the hinge frame 48, may prevent the hinge frame 48from being bent or deformed, and may also maintain an installationposition of the hinge case 47.

When the foaming solution is injected into the main door 40, a surfacearea can be increased, and thus adhesion with the foaming solution isenhanced. Also, the foaming solution may pass through the frame openings485, and thus flowability of the foaming solution may be improved. Whenthe insulation is molded, the hinge frame 48 may be buried and fixed inthe insulation.

The sub-hinges 51 and 52 may include an upper hinge 51 which isinstalled at an upper end of the sub-door 50 and a lower hinge 52 whichis installed at a lower end of the sub-door 50. And the upper hinge 51and the lower hinge 52 may extend laterally toward the hinge hole 433,and may be coupled at an inside of the main door 40.

Therefore, the sub-hinges 51 and 52 may be installed at accuratepositions, and may have a structure which extends laterally.Accordingly, since there is not an interfering structure with thesub-hinges 51 and 52 at a gap between the main door 40 and the sub-door50, a distance between the main door 40 and the sub-door 50 may bemaintained in a very narrow state, and the exterior may be furtherenhanced. Also, since the distance between the main door 40 and thesub-door 50 is maintained in the very narrow state, and deflection ofthe sub-door 50 is effectively prevented, the interference with the maindoor 40 upon the rotation of the sub-door 50 may be prevented.

A hinge cover 53 which shields the upper hinge 51 and guides access ofan electric wire of the sub-door 50 may be further provided at an upperside of the upper hinge 51.

FIG. 9 is an exploded perspective view of the main door and the displayunit. And FIGS. 10A and 10B are partial perspective views illustratingan installing state of the display unit.

As illustrated in the drawings, the display unit 60 may be provided atthe opening part 403 of the main door 40. The display unit 60 serves todisplay an operation state of the refrigerator 1 and also to operate therefrigerator 1, and may be formed so that the user recognizes throughthe sub-door 50 from an outside when the sub-door 50 is in thetransparent state. That is, the display unit 60 may not be visible fromthe outside while the sub-door 50 is in the opaque state, but mayindicate a variety to information to the outside while the sub-door 50is in the transparent state.

The display unit 60 may include a display 61 which displays stateinformation of the refrigerator 1, and various operating buttons 62which set the operation of the refrigerator 1. The operation of therefrigerator 1 may be operated by the operating buttons 62.

The display unit 60 may be separably provided at a lower end of theopening part 403. Therefore, when it is necessary to check or repair thedisplay unit 60, the display unit 60 may be separated. And after themain door 40 is assembled, the display unit 60 which is assembled as aseparate module may be simply installed. Also, the display unit 60 whichhas a necessary function according to a specification of therefrigerator 1 may be selectively installed.

To install and separate the display unit 60, a display installingprotrusion 435 may be formed at both inner side surfaces of the openingpart 403. And a display connection part 436 for electrical connectionwith the display unit 60 may be provided at the lower end of the openingpart 403.

The display installing protrusion 435 may be formed by protruding a sidesurface of the opening part 403, more specifically, a part of the doorliner 42 and a part of the door frame 43. That is, the displayinstalling protrusion 435 may be formed by coupling a liner sideinstallation part 4352 and a frame side installation part 4351 to eachother, and may be formed in a protrusion shape having a circular crosssection. Therefore, when the display unit 60 is installed, the displayinstalling protrusion 435 is maintained in an installed state, and thuscoupling between the door liner 42 and the door frame 43 may be morefirmly maintained. A plurality of display installing protrusions 435 maybe formed and may be arranged vertically.

The display installing protrusion 435 has a structure which is matchedwith a display guide 634 formed at both of left and right side surfacesof the display unit 60. The display guide 634 has a structure which isopened downward. Therefore, when the display unit 60 is moved downwardfrom an upper side, the display installing protrusion 435 and thedisplay guide 634 are coupled to each other. And in a state in which thedisplay unit 60 is installed, the display unit 60 may be seated andfixed to the lower end of the opening part 403.

The display connection part 436 may be formed at a bottom surface of thedoor liner 42. The display connection part 436 may be formed to berecessed or stepped downward, and may be formed so that at least a partof the display unit 60 is inserted therein when the display unit 60 isinstalled.

And a door connector 4361 may be provided at the display connection part436. The door connector 4361 may be connected with an electric wirewhich supplies electric power for an operation of the display unit 60and transmits a signal, and may be electrically connected with thedisplay unit 60 by a separable structure of the display 61.

That is, the door connector 4361 may protrude upward from a bottomsurface of the display connection part 436, and may be coupled andelectrically connected to a display connector 651 provided at a bottomof the display unit 60 when the display unit 60 is installed.

A plurality of door connectors 4361 may be provided, and may be formedseparately according to functions of the display unit 60. That is, thedoor connectors 4361 may be independently formed corresponding to thedisplay 61 and the operating buttons 62 of the display unit 60, and mayalso be formed so that the separate electric power and signal aretransmitted to each of them.

In some cases, a case extension part 635 may be formed at a lower end ofa rear surface of the display unit 60. Also, a screw hole 6351 in whicha screw is fastened may be formed at the case extension part 635, andthus the display unit 60 may be maintained in a coupled state to themain door 40.

FIG. 11 is a cross-sectional view illustrating an installed state of thedisplay unit. And FIG. 12 is an exploded perspective view of a displayassembly.

As illustrated in the drawings, the display unit 60 may include an outercase 63 which forms an external appearance, an inner case 64 which isprovided inside the outer case 63, a display PCB 65 and a display cover66.

The outer case 63 may form an entire exterior of the display unit 60,and can have an accommodation space formed therein to accommodate theinner case 64.

The accommodation space is opened forward, and a connector opening 631for coupling to the door connector 4361, through which the electric wireconnected to the display connector 651 passes, may be formed at a bottomsurface of the accommodation space. The display connector 651 may beprovided at a lower side of the connector opening 631, and in somecases, the display connector 651 may be fixed to the connector opening631.

Therefore, when the display unit 60 is installed at the opening part 403of the main door 40, the display connector 651 and the door connector4361 may be coupled and connected to each other by moving the displayunit 60 up and down. By such a connection, the power supplying and thesignal transmitting to the display unit 60 may be enabled.

A plurality of case coupling protrusions 632 which protrude to becoupled to the inner case 64 are formed at inner upper and lower ends ofthe accommodation space. The case coupling protrusions 632 may be formedat an opened entrance side of the accommodation space, and may be formedat regular intervals.

A case support part 633 which supports the inner case 64 may be formedto protrude inward from both of left and right sides of an inner surfaceof the accommodation space. A screw hole 6331 in which a screw isinserted may be further formed at the case support part 633, and theinner case 64 may be installed and fixed to the case support part 633.

The display guide 634 may be formed at both of left and right sidesurfaces of the outer case 63. The display guide 634 may be formed in arib shape which protrudes from both of the left and right side surfacesof the outer case 63. And the display guide 634 may be formed to beopened downward, and the display installing protrusion 435 may beinserted through an opened lower side thereof.

The display guide 634 may be formed so that a width thereof becomesnarrower upward from an opened entrance 6343 thereof. An upper end 6341of the display guide 634 may be formed to have the same size as adiameter of the display installing protrusion 435. Therefore, thedisplay installing protrusion 435 may be easily inserted into thedisplay guide 634, and may be restricted by the upper end 6341 of thedisplay guide 634.

Also, a fixing part 6342 which protrudes inward may be further formed atthe display guide 634. A distance between the fixing parts 6342 may beformed somewhat smaller than the diameter of the display installingprotrusion 435. Therefore, the display guide 634 may be elasticallydeformed while passing through the fixing part 6342, and may be fittedand fixed when being moved to the upper end 6341 of the display guide634.

The inner case 64 may be injection-molded with a plastic material, andmay provide a space in which the display PCB 65 is installed. A centerof the inner case 64 may be formed to be recessed with a sizecorresponding to the display PCB 65, and a plurality of case couplinggrooves 641 are formed at a perimeter of the inner case 64, and the casecoupling protrusion 632 is coupled therein.

A case seating part 642 which extends laterally and is seated on thecase support part 633 may be formed at both side surfaces of the innercase 64. The inner case 64 is coupled to the outer case 63 by a screwfastened into a screw hole 6421 of the case seating part 642.

A case hole 643 may be formed at one side surface of the inner case 64.The case hole 643 serves as a passage of the electric wires connected tothe display PCB 65, and the electric wires may pass through the casehole 643, and may be connected to the display connector 651 through theconnector opening 631.

The display PCB 65 may be accommodated in a space formed inside theinner case 64. The display 61 and the plurality of operating buttons 62may be installed at the display PCB in the form of a module. Andelements on the display PCB 65 may be covered and sealed with a resinmaterial for waterproofing and moisture-proofing.

The display 61 may be formed in a panel type which displays theoperation state and operation information of the refrigerator 1. And theplurality of operating buttons 62 may be provided at both of left andright sides of the display 61, and may be formed to be operated by auser's operation which pushes the display cover 66.

When the display PCB 65 is installed at the inner case 64, the innercase 64 is accommodated inside the outer case 63, and the display 61 maybe coupled so as to shield an opening of the outer case 63. Therefore,the display PCB 65 and the inner case 64 may be shielded by the display61.

The display cover 66 may be formed to have a size corresponding to anopened front surface of the outer case 63. Therefore, the display cover66 may form an exterior of a front surface of the display unit 60. And acenter of the display cover 66 may be formed so that information outputfrom the display 61 is projected therethrough. The display 61 may beexposed through an opening of the display cover 66, or may be exposed toan outside by forming a part of the display cover 66 to be transparent.

The plurality of operating buttons 62 may be provided at both of theleft and right sides of the display 61. The plurality of operatingbuttons 62 may also be correspondingly indicated on both sides of thedisplay cover 66. The operating buttons 62 indicated on the displaycover 66 are not actual operating buttons 62, but are indicated atcorresponding positions, and may be touched or pushed by the user.

A case fixing member 661 which installs and fixes the display cover 66may be formed to protrude from both of left and right side ends of thedisplay cover 66. An end of the case fixing member 661 may be formed ina hook shape, and may be hooked and restricted by a case restrictinggroove 636 formed at both side surfaces of the outer case 63, and thusthe display cover 66 may be installed and fixed.

FIG. 13 is a cross-sectional view taken along line 13-13′ of FIG. 1 .

As illustrated in the drawing, the door lighting unit 49 may be providedat an upper portion of the main door 40. The door lighting unit 49 maybe formed at a space between the door liner 42 and the door frame 43. Ofcourse, an installation position of the door lighting unit 49 is notlimited, and may be formed at one of the door liner 42 and the doorframe 43, and may be disposed at a position which illuminates the insideof the opening part 403.

The door lighting unit 49 may include a lamp case 491 which is installedinside the main door 40, a lamp PCB 492 which is provided at one side ofthe lamp case 491 and at which a plurality of LEDs 4921 are disposed,and a lamp cover 493 which shields an opened surface of the lamp case491 and is exposed through the opening part 403.

The lamp cover 493 may be formed to extend long along the door liner 42,and includes a recessed part 4914 which forms a recess space therein toaccommodate the lamp PCB 492. Specifically, a surface of the recessedpart 4914 which faces the lamp PCB 492 may be formed to be rounded, andlight emitted from the lamp PCB 492 is reflected by a rounded surface4915 having a predetermined curvature, and directed to the lamp case491. A film which increases the reflectivity of the light may beattached to or coated on an inner surface of the recessed part 4914,particularly, the rounded surface 4915.

A lamp PCB installation part 4913 at which the lamp PCB 492 is installedmay be formed at one surface which faces the rounded surface 4915. Thelamp PCB installation part 4913 enables the lamp PCB 492 to be installedand fixed in a direction perpendicular to the lamp cover 493. The lampPCB installation part 4913 and the lamp PCB 492 are located above thedoor frame 43 so as to be covered by an end of the door frame 43 whenbeing seen from a lower side. Therefore, the LEDs 4921 may be covered bythe end of the door frame 43 without an additional bezel, and thus aphenomenon in which the light looks as if forming a lump may beprevented.

A first case installation part 4911 and a second case installation part4912 may be formed at both ends of the recessed part 4914. The firstcase installation part 4911 and the second case installation part 4912may be installed to be in surface contact with inner side surfaces ofthe door liner 42 and the door frame 43, respectively, and thus the lampcase 491 may be hooked and restricted or adhered inside the main door40.

Cover insertion grooves 4916 and 4917 may be formed at the first caseinstallation part 4911 and the second case installation part 4912. Thecover insertion grooves 4916 and 4917 may be formed to be stepped, andthus a space in which both ends of the lamp cover 493 are inserted whenthe lamp case 491 is installed may be formed between the first caseinstallation part 4911 and the door liner 42 and between the second caseinstallation part 4912 and the door frame 43.

The lamp cover 493 may be formed so that the light reflected by therounded surface 4915 of the recessed part 4914 is transmittedtherethrough. The lamp cover 493 serves to shield an opening of therecessed part 4914 and also to shield a space between the door liner 42and the door frame 43.

The lamp cover 493 may be formed to be transparent or translucent, suchthat the light reflected by the rounded surface 4915 and uniformlyspread is transmitted therethrough. Therefore, the light passing throughthe lamp cover 493 can illuminate the inside of the refrigerator 1 viaan indirect illumination method, and can have an effect like surfaceemitting.

To effectively diffuse the light, a film may be attached to or coated onthe lamp cover 493. And in some cases, when the lamp cover 493 isinjection-molded, particles or a material for diffusing the light may beadded.

In some cases, cover fixing parts 4931 and 4932 which are inserted intothe cover insertion grooves 4916 and 4917 may be formed to protrude fromboth ends of the lamp cover 493 so that the lamp cover 493 is installedand fixed. The cover fixing parts 4931 and 4932 formed at both sides ofthe lamp cover 493 may be coupled or fitted inside the cover insertiongrooves 4916 and 4917 in the form of a hook, and thus the lamp cover 493may be installed and fixed.

The door lighting unit 49 may be selectively turned on/off by a user'soperation. When the door lighting unit 49 is turned on, the rear surfaceof the sub-door 50 and the opening part 403 become bright. When theinside of the refrigerator 1 is brighter than an outside of therefrigerator 1 by turning on the door lighting unit 49, the lightemitted by the door lighting unit 49 is transmitted through the sub-door50. Therefore, the sub-door 50 may be seen to be transparent by theuser, and thus the accommodation space inside the main door 40 may beseen from an outside through the sub-door 50.

In some cases, the main lighting unit 85 may be separately providedinside the refrigerator compartment 12. When the main lighting unit 85is turned on/off, the space inside the refrigerator 1 may be seen fromthe outside through the sub-door 50. The main lighting unit 85 providedinside the refrigerator compartment 12 may be turned on/off togetherwith the door lighting unit 49, or may be independently turned on/off.

A heater support part 432 which protrudes backward may be formed at therear surface of the frame stepped part 431. The heater support part 432may be formed along a perimeter of the frame stepped part 431, and maybe formed to protrude backward. And a protruding position of the heatersupport part 432 is located at an outside (an upper side in FIG. 13 ) ofthe frame stepped part 431 so that the frame heater 4321 is located atan outer end of the frame stepped part 431.

The frame heater 4321 can heat a corner of the frame stepped part 431 atwhich there is a high possibility of dew condensation. The corner of theframe stepped part 431 is a portion which is in contact with an outerportion of the sub-door gasket 591, has a relatively low temperature, isin contact with external air, and thus has the high possibility of dewcondensation. Therefore, the outside of the frame stepped part 431 isheated by the frame heater 4321, and the dew condensation can beprevented.

In some cases, door restricting members, such as magnets, may beprovided at positions corresponding to the main door 40 and the sub-door50, respectively. The door restricting members can enable the sub-door50 itself to be restricted to the main door 40 without a separaterestricting structure, and thus prevent the sub-door 50 from beingundesirably opened by an inertial force generated when the main door 40is rotated.

For example, a first magnet installation part 430 may be formed at aninner side surface of the door frame 43 which forms an upper surface ofthe opening part 403, and a first magnet 4301 may be installed and fixedto the first magnet installation part 430.

A magnet installation part 572 may be formed at an upper portion of thesub-door 50 corresponding to the first magnet installation part 430, anda second magnet 5721 may be installed and fixed to the second magnetinstallation part 572. The second magnet installation part 572 may beformed at an inner side surface of an upper cap decoration 57 whichforms an upper surface of the sub-door 50, and thus the second magnet5721 is not exposed to the outside.

When the sub-door 50 is closed, the first magnet 4301 and the secondmagnet 5721 are located at positions which face each other, and alsodisposed so that facing surfaces thereof have different polarities fromeach other. Therefore, the sub-door 50 can be maintained in a closedstate by an attraction between the first magnet 4301 and the secondmagnet 5721. Of course, when a rotating force of the sub-door 50 appliedby a user's operation is larger than a magnetic force of the firstmagnet 4301 and the second magnet 5721, the sub-door 50 may be rotated.

When the first magnet 4301 and the second magnet 5721 are located on thesame extension line, the magnetic force may be applied strongly. Anarrangement structure of the first magnet 4301 and the second magnet5721 is in parallel with an extending direction of a rotating axis ofthe sub-door 50. Therefore, when the sub-door 50 starts to be opened,the first magnet 4301 and the second magnet 5721 cross each other, andthus the magnetic force may be considerably weakened. Accordingly, afterthe sub-door 50 is rotated at a predetermined angle, opening of thesub-door 50 may be smoothly performed.

In some cases, the cap decoration 45 may be provided at the upper end ofthe main door 40. The foaming solution may be injected into an internalspace formed by the outer plate 41, the door liner 42, the door frame 43and the cap decoration 45, and thus the insulation may be formedtherein. An opening device accommodation part 452 may be formed at thecap decoration 45 to be recessed downward. The opening deviceaccommodation part 452 may be shielded by a cap decoration cover 453.

FIG. 14 is an exploded perspective view of an installation structure ofa door opening device according to the implementation of the presentdisclosure. And FIG. 15 is a view illustrating an operation state of thedoor opening device.

As illustrated in the drawings, the opening device accommodation part452 may be formed at the cap decoration 45 on an upper surface of themain door 40. And a door opening device 70 may be provided inside theopening device accommodation part 452. An opened upper surface of theopening device accommodation part 452 is shielded by the cap decorationcover 453.

The door opening device 70 for automatically opening the main door 40may include a driving motor 72 which is provided inside an openingdevice case 71, a push rod 74 which pushes and opens the main door 40,and gears 73 which transmits power of the driving motor 72 to the pushrod 74.

A rack gear 741 which is engaged with the gears 73 may be formed at anouter surface of the push rod 74, and thus may be inserted and withdrawnthrough a rod hole 4511 formed at the rear surface of the main door 40.

In some cases, the push rod 74 may be formed to have a predeterminedcurvature. Therefore, even when the main door 40 is rotated, a front endof the push rod 74 may continuously push the cabinet 10 while beingmaintained in a stably contacting state with a front surface of thecabinet 10, and thus may open the main door 40.

In a state in which the user is holding food and thus cannot use his/herhands, the main door 40 may be rotated at a predetermined angle by thedoor opening device 70, and thus the user may put a part of his/her bodylike an elbow therein, and may open the main door 40.

For example, by the operation of the door opening device 70, the maindoor 40 may be opened so that a distance D between the main door 40 andthe adjacent refrigerator compartment door 20 is about 90 mm. A rotatingangle of the main door 40 may be arpimd 24° to 26°. When therefrigerator compartment door 20 is automatically opened by the distanceD, the user may put the elbow or a part of his/her body in an opened gapof the refrigerator compartment door 20, and may additionally open therefrigerator compartment door 20 even while holding an object and thuscannot use his/her hands.

Of course, since the door opening device 70 is disposed inside the capdecoration 45 having a limited width, a length of the push rod 74 whichis inserted and withdrawn may be limited. Therefore, to minimize thelength of the push rod 74, the door opening device 70 may be located ata position as close as possible to a rotating axis of the main hinge 401so that a force for opening the main door 40 may be effectivelytransmitted. And to ensure an opening angle of the main door 40, thegears 73 may be combined and arranged so that the push rod 74 having thepredetermined length is maximally withdrawn.

The door opening device 70 may be installed at the opening deviceaccommodation part 452 by a screw. The door opening device 70 may besupported at an inside of the opening device accommodation part 452 by ashock absorbing member through which the screw passes, and thusvibration and noise generated when the door opening device 70 isoperated may be prevented.

In some cases, the door opening device 70 may be selectively driven bythe user's operation, and may rotate the main door 40 by an operation ofthe driving motor 72 when a door opening signal is input by the user.Since the user's hands cannot be used, an operation input of the dooropening device 70 may be performed in a position detecting method or amotion detecting method, instead of a direct input method by the user'sbody contact. This will be described again below in detail.

FIG. 16 is a cross-sectional view taken along line 16-16′ of FIG. 1 .

As illustrated in the drawing, in the main door 40, an externalappearance formed at both sides of the opening part 403 may be formed bycoupling the outer plate 41, the door frame 43 and the door liner 42.

A front support part 437 which is bent to support the outer plate 41 maybe formed at a front end of the door frame 43. A front accommodationpart 4371 in which an end of the outer plate 41 is introduced in a bentstate may be formed at an end of the front support part 437.

The end of the outer plate 41 which is located at the frontaccommodation part 4371 forms a multi-bent part 411 which iscontinuously bent several times. The multi-bent part 411 forms one endof the opening part 403. The one end of the opening part 403 at whichthe multi-bent part 411 is located is close to a handle 561 formed at asecond side frame 56 of the sub-door 50.

The multi-bent part 411 is bent at a portion forming the front surfaceof the main door 40 to have a predetermined slope, and forms a firstbent part 4111. An inclined surface of the first bent part 4111 may beformed to be directed toward the opening part 403, and an end of thefirst bent part 4111 forms one end of the opening part 403.

A second bent part 4112 which is bent in a direction opposite to thefirst bent part 4111 may be formed at the end of the first bent part4111. And a third bent part 4113 which is bent in parallel with thefront surface of the main door 40 may be formed at an extending end ofthe second bent part 4112. The second bent part 4112 and the third bentpart 4113 may be located inside the front accommodation part 4371, andmay be in close contact with and supported by the front support part437.

Therefore, the one end of the opening part 403 at which the multi-bentpart 411 may be formed is a portion at which the handle 561 of thesub-door 50 is located, and the user's hand comes in and out frequently.In a process in which the user's hand comes in and out, the user's handmay be in contact with one end of the opening part 403. Here, the user'shand may smoothly come in and out without being caught or scratched bythe inclined surface of the first bent part 4111. At the same time,strength may be reinforced by the multi-bent part 411, and the outerplate 41 may be prevented from being deformed by a shock generated whilethe user's hand comes in and out frequently.

The handle 561 forms one side surface of the sub-door 50, and may beformed long vertically, and also formed to have a predetermined spacebetween the one side surface of the sub-door 50 and one end of theopening part 403, such that the user puts his/her hand therein and thenpulls.

In some cases, the frame heater 4321 and the heater support part 432 maybe formed to protrude from the rear surface of the frame stepped part431 of the door frame 43 and thus to heat the frame stepped part 431,thereby preventing the dew condensation.

FIG. 17 is a perspective view of the sub-door. And FIG. 18 is anexploded perspective view of the sub-door when being seen from a front.And FIG. 19 is an exploded perspective view of the sub-door when beingseen from a rear.

As illustrated in the drawings, the sub-door 50 may be formed in a shapecorresponding to that of the opening part 403. The sub-door 50 mayinclude a panel assembly 54 which may be formed by stacking a pluralityof glass layers at regular intervals, side frames 55 and 56 which formsboth side surfaces of the sub-door 50, a sub-door liner 59 which forms aperimeter of the rear surface of the sub-door 50, and the upper capdecoration 57 and a lower cap decoration 58 which forms an upper surfaceand a lower surface of the sub-door 50.

The panel assembly 54 may form an entire front surface of the sub-door50. The panel assembly 54 may include a front panel 541 which forms anexterior of a front surface thereof, and an insulation panel 542 whichmay be formed to be spaced apart from a rear surface of the front panel541. A plurality of insulation panels 542 may be provided, and a spacerbar 543 is provided between the front panel 541 and the insulation panel542 and between the plurality of insulation panels 542.

The front panel 541 and the insulation panel 542 may be formed of glassor a see-through material, and thus the inside of the refrigerator 1 maybe selectively seen through. And the front panel 541 and the insulationpanel 542 may have an insulating material or an insulating structure,and may be formed to prevent a leak of cooling air in the refrigerator1. A configuration of the panel assembly 54 will be described below indetail.

The side frames 55 and 56 may form both of left and right side surfacesof the sub-door 50. The side frames 55 and 56 may be formed of ametallic material, and serves to connect the panel assembly 54 with thedoor liner 42.

The side frames 55 and 56 may include a first side frame 55 forming onesurface at which the sub-hinges 51 and 52 are installed, and a secondside frame 56 at which the handle 561 enabling the user to perform arotating operation is formed.

The first side frame 55 may be formed long vertically, and also formedto connect between the upper hinge 51 and the lower hinge 52.Specifically, hinge insertion parts 551 and 552 in which the upper hinge51 and the lower hinge 52 are inserted are formed at upper and lowerends of the first side frame 55, respectively. The hinge insertion parts551 and 552 are formed at the upper and lower ends of the first sideframe 55 to be recessed, and may be formed to have a correspondingshape, such that a part of the upper hinge 51 and the lower hinge 52 ismatched therewith.

The first side frame 55 may be formed of a metallic material such asaluminum or a material having high strength, and may enable the upperhinge 51 and the lower hinge 52 to be maintained at accurateinstallation positions, such that the installation positions are notchanged by a weight of the sub-door 50. Therefore, the sub-door 50 maymaintain an initial installation position at the main door 40, and anouter end of the sub-door 50 and the opening part 403 of the main door40 may not interfere with each other when being rotated, and maymaintain a very closely contacting state with each other.

Like the first side frame 55, the second side frame 56 may be formed ofthe metallic material or the material having high strength. The secondside frame 56 may be formed to extend from the upper end of the sub-door50 to the lower end thereof, and may have the handle 561 which isrecessed to allow the user to put his/her hand therein.

The upper cap decoration 57 forms the upper surface of the sub-door 50,and connects upper ends of the first side frame 55 and the second sideframe 56, and is also coupled to an upper end of the panel assembly 54and an upper end of the sub-door liner 59.

An upper hinge installation part 571 may be formed at one end of theupper cap decoration 57. The upper hinge installation part 571 may berecessed so that the upper hinge 51 and the hinge cover 53 are installedtherein, and upper surfaces of the hinge cover 53 and the upper capdecoration 57 may form the same plane while the hinge cover 53 isinstalled.

The lower cap decoration 58 may form the lower surface of the sub-door50, and may connect lower ends of the first side frame 55 and the secondside frame 56, and is also coupled to a lower end of the panel assembly54 and a lower end of the sub-door liner 59.

A lower hinge installation part 581 may be formed at one end of thelower cap decoration 58. The lower hinge installation part 581 can berecessed so that the lower hinge 52 is installed therein. A detectiondevice accommodation part (or detection device accommodation bracket)582 in which a second detection device 81 and a knock detection device82 are installed may be formed at the lower cap decoration 58. Thedetection device accommodation part 582 may be shielded by anaccommodation part cover (or accommodation groove cover) 583.

The second detection device 81 which is installed at the lower capdecoration 58 is a device which checks a user's approach, and the knockdetection device 82 is a device which detects a user's knockingoperation on the sub-door 50. The second detection device 81 and theknock detection device 82 may be attached to the rear surface of thefront panel 541, and may be provided at a lower end of the front panel541 close to the second side frame 56. By the second detection device 81and the knock detection device 82, the sub-door 50 may selectivelybecome transparent, and thus an inside of the sub-door 50 may be seenthrough. Detailed structures of the second detection device 81 and theknock detection device 82 will be described below.

The sub-door liner 59 forms a shape of a perimeter of the rear surfaceof the sub-door 50, and may be injection-molded with a plastic material.The sub-door liner 59 is coupled to the first side frame 55, the secondside frame 56, the upper cap decoration 57 and the lower cap decoration58. And the foaming solution is injected into an internal space of aperimeter of the sub-door 50 formed by the sub-door liner 59, and theinsulation may be filled therein, and thus an insulation structure ofthe perimeter of the sub-door 50 can be provided.

That is, the insulation structure may be formed at a center portion ofthe sub-door 50 by the insulation panel 542 forming the panel assembly54, and a perimeter of the panel assembly 54 may have the insulationstructure by the insulation.

The sub-door gasket 591 is provided at a rear surface of the sub-doorliner 59. The sub-door gasket 591 may be formed to be in close contactwith the main door 40 when the sub-door 50 is closed. Therefore, theleak of the cooling air between the main door 40 and the sub-door 50 maybe prevented.

FIG. 20 is a cut-away perspective view taken along line 20-20′ of FIG.17 . And FIG. 21 is an exploded perspective view of the panel assemblyaccording to the implementation of the present disclosure.

As illustrated in the drawings, an entire exterior of the sub-door 50may be formed by the panel assembly 54, and the first side frame 55 andthe second side frame 56 are coupled to both ends of the panel assembly54. And the foaming solution is filled in a space formed by the panelassembly 54, the first side frame 55 and the second side frame 56, andforms the insulation.

The panel assembly 54 may include the front panel 541 which forms theentire front surface of the sub-door 50, at least one or more insulationpanels 542 which are disposed at a rear of the front panel 541, and thespacer bar 543 which supports between the front panel 541 and theinsulation panel 542 and between the plurality of insulation panels 542.

The front panel 541 may be formed of a glass material which isselectively seen through according to a light transmittance andreflectivity, and thus may be referred to as a half mirror. The frontpanel 541 may be formed so that a rear of the sub-door 50 is selectivelyseen through according to ON/OFF of the main lighting unit 85 or thedoor lighting unit 49 in the refrigerator 1.

That is, in a state in which the door lighting unit 49 is turned on,light inside the refrigerator 1 penetrates the front panel 541, and thusthe front panel 541 looks transparent. Therefore, a space inside therefrigerator 1 located at the rear of the sub-door 50 or theaccommodation space formed at the main door 40 may be seen from theoutside while the sub-door 50 is closed.

In a state in which the door lighting unit 49 is turned off, the lightmay not penetrate the front panel 541, but rather be reflected, and thusthe front panel 541 can serve as a mirror surface. In this state, thespace inside the refrigerator located at the rear of the sub-door 50 orthe accommodation space formed at the main door 40 may not be seen fromthe outside.

A bezel 5411 may be formed along a perimeter of the rear surface of thefront panel 541. The bezel 5411 may be formed so that the light is nottransmitted therethrough, and thus the side frames 55 and 56, the uppercap decoration 57, the lower cap decoration 58 and the spacer bar 543which are coupled to the front panel 541 are prevented from beingexposed forward through the front panel 541.

The second detection device 81 and the knock detection device 82 may bedisposed at the bezel 5411 which is formed at the lower end of the frontpanel 541, and the knock detection device 82 is disposed so as to becovered.

In some cases, in the bezel 5411 which may be formed at the lower end ofthe front panel 541, a penetration part 5412 may be formed at a positioncorresponding to the second detection device 81. The penetration part5412 may be formed in a shape corresponding to a front surface of thesecond detection device 81, and the bezel 5411 is not printed thereon.

That is, the bezel 5411 having a predetermined width may be printedalong a perimeter of the front panel 541, except for the penetrationpart 5412. The penetration part 5412 can enable the light emitted fromthe second detection device 81 to not interfere with the bezel 5411, butrather to pass through the front panel 541 and thus to be transmittedand received.

The front surface of the second detection device 81 which is in contactwith the penetration part 5412 may be formed to have the same color asthat of the bezel 5411. Therefore, even in a state in which the frontsurface of the second detection device 81 is exposed by the penetrationpart 5412, an area of the penetration part 5412 may not be easilyexposed, and may have a sense of unity with the front panel 541.

In some cases, the first side frame 55 and the second side frame 56 maybe installed at the rear surface of the front panel 541. The first sideframe 55 and the second side frame 56 may be adhered to both side endsof the rear surface of the front panel 541, respectively, and may beadhered to an inside of an area of the bezel 5411.

The spacer bar 543 may be formed at the perimeter of the rear surface ofthe front panel 541. The spacer bar 543 can enable the front panel 541and the insulation panel 542 to be spaced apart from each other, andalso serves to seal therebetween.

The spacer bar 543 may also be disposed between the plurality ofinsulation panels 542. The front panel 541, the insulation panel 542 andthe plurality of spacer bars 543 may be bonded to each other by anadhesive, and a sealant may be coated to seal among the front panel 541,the insulation panel 542 and the spacer bar 543.

The insulation panel 542 may be formed to have a size smaller than thatof the front panel 541, and may be located within an internal area ofthe front panel 541. And the insulation panel 542 may be chemicalstrengthening glass in which glass is soaked in an electrolyte solutionat a glass transition temperature or more, and thus chemicallystrengthened.

A low-radiation coating layer for reducing heat transfer into thestorage compartment due to radiation may be formed at a rear surface ofthe insulation panel 542. Glass on which the low-radiation coating layermay be formed is referred to as low-E glass. The low-radiation coatinglayer may be formed by sputtering silver or the like on a surface of theglass.

A sealed space between the front panel 541 and the insulation panel 542and a sealed space between the plurality of insulation panels 542 whichare formed by the spacer bar 543 may create a vacuum state so as to beinsulated.

In some cases, an inert gas for the insulation, such as argon, may befilled in the sealed space between the front panel 541 and theinsulation panel 542 and the sealed space between the plurality ofinsulation panels 542. Inert gas generally has more excellent insulationproperty than that of air. Therefore, insulation performance may beensured by forming a predetermined space between the front panel 541 andthe insulation panel 542 and between the plurality of insulation panels542 in which the inert gas is filled.

The insulation panel 542 may be formed in a single panel, and may beinstalled to be spaced apart from the front panel 541. In some cases,two or more insulation panels 542 may be provided to be spaced apartfrom each other.

Hereinafter, a structure of the front panel 541 having variousapplicable types of half mirror structures will be described.

FIG. 22 is a cross-sectional view schematically illustrating an exampleof a front panel of the panel assembly.

As illustrated in the drawing, the front panel 541 according to anexample implementation may include a glass layer 5413 which forms anexterior, a vacuum deposition layer 5414 which may be formed at a rearsurface of the glass layer 5413, a bezel print layer 5415 which may beformed at a rear surface of the vacuum deposition layer 5414, and atransparent print layer 5416 which forms entire rear surfaces of thebezel print layer 5415 and the vacuum deposition layer 5414.

Specifically, the glass layer 5413 may be formed of green glass which iswidely used as transparent glass, and can form an entire surface of thefront panel 541. Of course, various other transparent glass materialsother than the green glass, such as white glass, may be used.

The vacuum deposition layer 5414 can allow the front panel 541 to have ahalf glass property, and may be formed at the rear surface of the glasslayer 5413 by vacuum-depositing a titanium compound (e.g., TiO2). Thatis, the vacuum deposition layer 5414 may be formed at the entire rearsurface of the glass layer 5413. While the door lighting unit 49 is notturned on, the light may be reflected by the vacuum deposition layer5414, and thus the front panel 541 can look like a mirror when beingseen from a front.

The bezel print layer 5415 may form the perimeter of the rear surface ofthe front panel 541, and the bezel 5411 may be formed by the bezel printlayer 5415. The bezel print layer 5415 may be formed so that the lightis not transmitted therethrough even while the door lighting unit 49 isturned on, and thus elements which are disposed along the perimeter ofthe rear surface of the front panel 541 may be shielded.

The transparent print layer 5416 may be formed at the entire rearsurface of the front panel 541 including the bezel print layer 5415 andthe vacuum deposition layer 5414. The transparent print layer 5416 maybe formed to be transparent, such that the light is transmittedtherethrough, and serves to protect the front panel 541 while the frontpanel 541 or the panel assembly 54 is processed.

In particular, the transparent print layer 5416 can prevent the vacuumdeposition layer 5414 from being damaged. For coupling with theinsulation panel 542, the front panel 541 may be formed so that thespacer bar 543 or the like is attached thereto. The front panel 541 maybe manufactured separately from the insulation panel 542, and thentransported. In this process, when the transparent print layer 5416 isnot provided, the vacuum deposition layer 5414 may be damaged, and thusmay not perform a half glass function. Therefore, in a structure inwhich the vacuum deposition layer 5414 may be formed at the rear surfaceof the glass layer 5413, the transparent print layer 5416 should beprovided.

FIG. 23 is a cross-sectional view schematically illustrating anotherexample of the front panel of the panel assembly.

As illustrated in the drawing, the front panel 541 according to anotherexample implementation may include a glass layer 5413 which forms anexterior, a ceramic print layer 5417 which may be formed at a frontsurface of the glass layer 5413, and a bezel print layer 5415 which maybe formed at a rear surface of the glass layer 5413.

Specifically, the glass layer 5413 may be formed of a glass materialthrough which the light is transmitted, and also which is seen through.A glass material called dark gray glass which imperceptibly has a darkgray color in a transparent state may be used.

When the door lighting unit 49 is not turned on, and thus the frontpanel 541 is in a mirror-like state, the dark gray color of the glasslayer 5413 serves to subsidiarily provide a color sense which enablesthe front panel 541 to have a texture which looks like an actual mirror.

The ceramic print layer 5417 may be formed at the entire front surfaceof the glass layer 5413, and may be formed in a silk screen printingusing reflectance ink which reflects the light.

The reflectance ink can include the titanium compound (TiO2) as a maincomponent, a viscosity-controlling resin, an organic solvent, and anadditive. The reflectance ink may be manufactured to have apredetermined viscosity for the silk screen printing.

The ceramic print layer 5417 may be formed to have a thickness ofapproximately 40 to 400 nm. The ceramic print layer 5417 may haveflatness similar to a mirror surface through the silk screen printingusing the reflectance ink, and may also be formed like the mirrorsurface when being reinforced by heating.

The ceramic print layer 5417 can be separately formed on the surface ofthe glass layer 5413, and can have a different refractive index fromthat of the glass. Therefore, some of the light incident from theoutside of the refrigerator 1 to the front panel 541 may be reflected bythe ceramic print layer 5417, and the rest may be reflected by the glasslayer 5413, and may have an effect like the mirror due to aninterference effect of the light which is reflected. That is, due to theinterference effect of the light which is reflected by a boundarysurface of another medium having a different refractive index, the frontpanel 541 may look like the mirror when being seen from an outside.

However, when the door lighting unit 49 is turned on, the light isemitted from the inside of the refrigerator 1 toward the glass layer5413, and the light transmitted through the glass layer 5413 passesthrough the ceramic print layer 5417. Therefore, the front panel 541 maylook transparent when being seen from the outside of the refrigerator 1,and the space in the refrigerator 1 may be visible.

The ceramic print layer 5417 may be formed so that the transmittance ofthe front panel 541 is about 20% to 30%. When the transmittance is 20%or less, it can be difficult to see through the space in therefrigerator 1 due to a low transparency of the front panel 541 evenwhile the door lighting unit 49 is turned on. And when the transmittanceis 30% or more, the space in the refrigerator 1 may be visible evenwhile the door lighting unit 49 is turned off, and thus the surfaceeffect like the mirror may not be expected. Therefore, for the halfmirror effect, it is preferable that transmittance of the front panel541 is about 20% to 30%.

And to form a surface having a high brightness, such as the mirrorsurface, the ceramic print layer 5417 can be reinforced by heating to apredetermined temperature. An organic component may be completelyremoved through the heating, and the titanium compound (TiO2) may becalcined on the glass layer 5413.

In some cases, when the front panel 541 is heated after the ceramicprint layer 5417 is printed by the silk screen printing, the heating maybe performed at a high temperature so that the organic component of thereflectance ink is completely removed, and the titanium compound iscalcined. However, when the heating is performed at an excessively hightemperature, bending may occur. Therefore, it is preferable that theheating be performed within a range at which the surface is notdeformed. And for removing of the organic component and calcination ofthe titanium compound, the front panel 541 may be heated in stages atdifferent temperatures.

The bezel print layer 5415 may form the perimeter of the rear surface ofthe front panel 541, and the bezel 5411 may be formed by the bezel printlayer 5415. The bezel print layer 5415 may be formed so that the lightis not transmitted therethrough even while the door lighting unit 49 isturned on, and thus may shield the elements which are disposed along theperimeter of the rear surface of the front panel 541.

In some cases, the bezel print layer 5415 may be formed in an inorganicprinting method (glass printing). The bezel print layer 5415 may beprinted using a ceramic pigment as a main component in which frit, aninorganic pigment and oil are mixed. Therefore, in the bezel print layer5415, the resin can be decomposed and volatilized by the heating in theglass reinforcing process, and the frit melts and covers the pigment,and then may be attached on the surface of the glass layer 5413.

Such an inorganic printing method has smaller fragments and higherdurability than an organic printing method. And a glass component maymelt and may be integrally molded with the glass layer 5413, and thus ina multi-layering process with the additional insulation panel 542, itmay be possible to reduce heat loss and also to provide an excellentadhesive property.

FIG. 24 is a cross-sectional view schematically illustrating stillanother example of the front panel of the panel assembly.

As illustrated in the drawing, the front panel 541 according to stillanother example implementation may include a glass layer 5413 whichforms an exterior, a hard coating layer 5418 which may be formed at afront surface of the glass layer 5413, and a bezel print layer 5415which may be formed at a rear surface of the glass layer 5413.

Specifically, the glass layer 5413 may be formed of a glass materialthrough which the light is transmitted, and also which is seen through.A glass material called gray glass which imperceptibly has a dark graycolor in a transparent state may be used.

The gray glass can have a somewhat brighter color than the dark grayglass described in the above-described example implementation. Thisdifference may be caused by a difference between the ceramic print layer5417 and the hard coating layer 5418 which are formed on the glass layer5413.

When the door lighting unit 49 is not turned on, and thus the frontpanel 541 is in the mirror-like state, the gray color of the glass layer5413 can serve to subsidiarily provide a color sense which enables thefront panel 541 to have a texture which looks like the actual mirror.

The hard coating layer 5418 may be formed at the entire front surface ofthe glass layer 5413, and also formed to have a light transmittance of25 to 50% and a reflectivity of 45 to 65%, and to have a half mirrorproperty, such that the transmittance and the reflectivity may besimultaneously increased.

The hard coating layer 5418 may be formed in a thickness of about 30 to80 nm, and may be configured with triple layers of iron, cobalt andchrome. Of course, one or two layers of the triple layers may beomitted, considering the transmittance, the reflectivity and a colordifference.

The hard coating layer 5418 may be formed in an atmospheric pressurechemical vapor deposition (APCVD) method in which a vaporized coatingsubstance may be formed on the entire surface of the glass layer 5413,or in a spraying method in which a liquid coating material is sprayed.

The hard coating layer 5418 may be separately formed on the surface ofthe glass layer 5413, and can have a different refractive index fromthat of the glass layer 5413. Therefore, some of the light incident fromthe outside of the refrigerator 1 to the front panel 541 may bereflected by the hard coating layer 5418, and the rest may be reflectedby the glass layer 5413. Therefore, the front panel 541 may have aneffect like the mirror due to an interference effect of the light whichis reflected. That is, due to the interference effect of the light whichis reflected by a boundary surface of another medium having a differentrefractive index, the front panel 541 may look like the mirror whenbeing seen from an outside.

However, when the door lighting unit 49 is turned on, the light isemitted from the inside of the refrigerator 1 toward the glass layer5413, and the light transmitted through the glass layer 5413 passesthrough the hard coating layer 5418. Therefore, the front panel 541 maylook transparent when being seen from the outside of the refrigerator 1,and the space in the refrigerator 1 may be visible.

The hard coating layer 5418 may be formed so that the transmittance ofthe front panel 541 is about 20% to 30%. When the transmittance is 20%or less, it is difficult to see through the space in the refrigerator 1due to a low transparency of the front panel 541 even while the doorlighting unit 49 is turned on. And when the transmittance is 30% ormore, the space in the refrigerator 1 may be visible even while the doorlighting unit 49 is turned off, and thus the surface effect like themirror may not be expected. Therefore, for the half mirror effect, it ispreferable that transmittance of the front panel 541 be between about20% to 30%.

The bezel print layer 5415 forms the perimeter of the rear surface ofthe front panel 541, and the bezel 5411 may be formed by the bezel printlayer 5415. The bezel print layer 5415 may be formed so that the lightis not transmitted therethrough even while the door lighting unit 49 isturned on, and thus may shield the elements which are disposed along theperimeter of the rear surface of the front panel 541. The bezel printlayer 5415 may be formed in the inorganic printing method.

FIG. 25 is a cross-sectional view of the sub-door.

As illustrated in the drawing, the side frames 55 and 56 are provided atboth sides of the panel assembly 54. The side frames 55 and 56 may beattached and fixed to the front panel 541, may be coupled to thesub-door liner 59 so as to form a space in which the insulation isaccommodated, and may also insulate the perimeter of the sub-door 50.

The second side frame 56 may be formed at a position which faces thefirst side frame 55, and may be configured to form another side surfaceof the sub-door 50. And a first front bent part 553 and a first rearbent part 554 may be formed at both ends of the first side frame 55.

The first front bent part 553 may be formed to be bent and thus to be incontact with the rear surface of the front panel 541, and may extend toa position of the spacer bar 543. Therefore, a temperature outside thesub-door 50 may be transferred to the rear surface of the front panel541 along the first side frame 55 formed of the metallic material, andthus the dew condensation at one side of the front panel 541 which is incontact with the first front bent part 553 may be prevented.

And a first heater installation groove 5531 at which a sub-door heater502 is installed may be further formed at the first side frame 55. Thefirst heater installation groove 5531 may be formed at an end of thefirst front bent part 553 so that the sub-door heater 502 is disposed ata position close to the spacer bar 543. Therefore, the sub-door heater502 may be vertically disposed long along the first side frame 55. Dueto a property of the first side frame 55 formed of the metallicmaterial, the dew condensation at the front panel 541 may be preventedby heating the rear surface of the front panel 541 which is in contactwith the first front bent part 553.

The first rear bent part 554 may be bent from a rear end of the firstside frame 55, and coupled to the sub-door liner 59. The first rear bentpart 554 may be formed to support the sub-door liner 59, and may beformed to support a load transmitted through the sub-door gasket 591when the sub-door 50 is closed.

The second side frame 56 is provided at a position which faces the firstside frame 55, and may be configured to form still another side surfaceof the sub-door 50. The second side frame 56 may be formed to be locatedat a position close to one surface of the opening part 403 of the maindoor 40. And a second front bent part 562 and a second rear bent part563 may be formed at both ends of the second side frame 56.

The second front bent part 562 may extend from an end of the second sideframe 56, and may be recessed to form the handle 561 in which the user'shand is put. The handle 561 may be formed to be recessed toward alateral side of the panel assembly 54. Therefore, the handle 561 may notbe exposed, and only a part of the second side frame 56 may be exposedforward when being seen from a front.

And the second front bent part 562 can form the handle 561, and may beformed to extend from one end of the second side frame 56 and to be incontact with the rear surface of the front panel 541. Therefore, atemperature outside the sub-door 50 may be transferred to the rearsurface of the front panel 541 along the second side frame 56 formed ofthe metallic material, and thus the dew condensation at one side of thefront panel 541 which is in contact with the second front bent part 562may be prevented.

Specifically, the second front bent part 562 may be recessed from anouter side further than the front panel 541 toward the front panel 541,and a recessed end may be formed to be recessed inward further than anouter end of the front panel 541. And the second front bent part 562 maybe located at a rear of the front panel 541, and thus the user may puthis/her hand into the handle 561 formed by the second front bent part562, and then may rotate the sub-door 50.

And a second heater installation groove 5621 at which the sub-doorheater 502 is installed may be further formed at the second front bentpart 562. The second heater installation groove 5621 enables thesub-door heater 502 to be disposed at a position close to the spacer bar543. Therefore, the sub-door heater 502 may be vertically disposed longalong the second side frame 56. Due to a property of the second sideframe 56 formed of the metallic material, the dew condensation at thefront panel 541 may be prevented by heating the rear surface of thefront panel 541 which is in contact with the second front bent part 562.

A portion of an inner side surface of the second front bent part 562which is in contact with the front panel 541 may be formed to berounded, and thus may allow the user to easily grip and pull forward theportion.

The second rear bent part 563 may be bent from a rear end of the secondside frame 56, and coupled to the sub-door liner 59. The rear bent part563 may be formed to support the sub-door liner 59, and may be formed tosupport the load transmitted through the sub-door gasket 591 when thesub-door 50 is closed.

FIG. 26 is an exploded perspective view illustrating a couplingstructure of the sub-door and the upper hinge. And FIG. 27 is a partialperspective view illustrating an installed state of the upper hinge.

As illustrated in the drawings, the upper hinge installation part 571which is recessed so that the upper hinge 51 and the hinge cover 53 areinstalled therein may be formed at the upper cap decoration 57 of thesub-door 50. The upper hinge installation part 571 may be formed at anupper end of the upper cap decoration 57, and may be formed to beconnected to the adjacent first side frame 55.

That is, the hinge insertion part 551 formed at an upper end of thefirst side frame 55 and the upper hinge installation part 571 of theupper cap decoration 57 may be connected to each other, and thus theupper hinge 51 may be installed at a corner of the sub-door 50 to whichthe upper hinge installation part 571 and the hinge insertion part 551are connected. In some cases, the lower cap decoration 58 provided atthe lower end of the sub-door 50 may have the same structure, and thusthe lower hinge 52 may be installed at a corner of the sub-door 50.

A hinge accommodation part 5711 which is recessed to have a shapecorresponding to the upper hinge 51 may be formed at the upper hingeinstallation part 571. And a hinge fixing hole 5712 in which the screwpassed through the upper hinge 51 is fastened may be formed at the hingeaccommodation part 5711.

And an electric wire guide part 5714 and an electric wire hole 5713through which an electric wire L disposed at the upper hinge 51 passesmay be formed at one side of the upper hinge installation part 571. Theelectric wire L guided through the electric wire guide part 5714 isconnected to the second detection device 81 and the knock detectiondevice 82, and guided to the upper cap decoration 57 via the lower capdecoration 58 and the second side frame 56. Then, the electric wire Lmay be introduced into the electric wire guide part 5714 through theelectric wire hole 5713 formed at the upper hinge installation part 571,and may be guided to an outside of the sub-door 50 through the electricwire guide part 5714. The electric wire L guided along the electric wireguide part 5714 is guided in an extending direction of the upper hinge51, and introduced into the main door 40 through the hinge hole 433 ofthe main door 40 together with one side of the upper hinge 51.

In some cases, the upper hinge 51 may be installed and fixed to theupper hinge installation part 571 by a screw, and may include a doorinstallation part 511 which is fixed to the sub-door 50, and a rotarycoupling part 512 which is rotatably coupled to the main door 40.

And the door installation part 511 may include a horizontal part 5111which is fixed to the upper hinge installation part 571, and a verticalpart 5112 which is fixed to the hinge insertion part 551 of the firstside frame 55. The horizontal part 5111 and the vertical part 5112 areformed perpendicularly to each other, and thus the upper hinge 51 may bemaintained in a fixed state to a corner of the upper end of the sub-door50.

The rotary coupling part 512 may be formed to extend from an end of thehorizontal part 5111 toward the outside of the sub-door 50. The rotarycoupling part 512 may be formed to be bent in one direction, and a hingeshaft 5121 may be formed at an extending end thereof. The hinge shaft5121 may be formed to extend downward from the plate-shaped rotarycoupling part 512.

And a cut-away part 5122 may be formed at the rotary coupling part 512to have the same shape as a shape that the rotary coupling part 512 isbent laterally. The cut-away part 5122 may be formed to be recessedinward from one side at which the hinge shaft 5121 is formed. And therotary coupling part 512 may be cut so as to be rounded in a rotatingradius direction of the sub-door 50 when the sub-door 50 is opened andclosed. Therefore, when the sub-door 50 is rotated to be opened whilethe upper hinge 51 is coupled to the main door 40, one end of the doorframe 43 forming the hinge hole 433 is inserted into the cut-away part5122.

And a flange 5123 which prevents a deformation of the rotary couplingpart 512 and reinforces strength may be formed along an outer end of therotary coupling part 512. The flange 5123 may be formed to extend in adirection which perpendicularly intersects with the rotary coupling part512.

A stopper 5124 may be further formed at one end of the rotary couplingpart 512. The stopper 5124 may be formed at one side of the rotarycoupling part 512 close to the hinge shaft 5121, and extends downward soas to interfere with one side of the main door 40 or the hinge hole 433while the sub-door 40 is rotated to be completely opened, and thusprevents the sub-door 50 from being further opened.

The hinge cover 53 may be formed to shield an opening of the upper hingeinstallation part 571 and also to shield the upper hinge 51 from anupper side thereof. The hinge cover 53 may include a cap decorationshielding part 531 which shields the upper hinge installation part 571,and a hinge shielding part 532 which shields the rotary coupling part512 of the upper hinge 51.

The cap decoration shielding part 531 may have a shape corresponding tothe upper hinge installation part 571, and may also have a plurality ofscrew holes 5311 so that a screw is directly fastened to the upper capdecoration 57, or the screw passing through the door installation part511 is moved in and out.

The hinge shielding part 532 may be formed to extend along a shape ofthe rotary coupling part 512 of the upper hinge 51, and may also beformed to cover the rotary coupling part 512 from an upper side thereof.And the hinge shielding part 532 is disposed to be somewhat spaced apartfrom the rotary coupling part 512, and thus to form a space between thehinge shielding part 532 and the rotary coupling part 512, and thus theelectric wire L passed through the electric wire guide part 5714 may beguided through the space between the hinge shielding part 532 and therotary coupling part 512.

FIG. 28 is a longitudinal cross-sectional view illustrating a couplingstructure of the upper hinge.

As illustrated in the drawing, the upper hinge 51 has a structure whichis installed and fixed to the upper hinge installation part 571 of theupper cap decoration 57, and shielded by the hinge cover 53.

And while the sub-door 50 is installed at the main door 40, the upperhinge 51 is inserted into the hinge hole 433, and the rotary couplingpart 512 of the upper hinge 51 is located inside the main door 40.

In this state, the hinge shaft 5121 of the upper hinge 51 may beinserted into a shaft installation part 438 of the main door 40. Theshaft installation part 438 may be fixed to the inside of the main door40 by a separate member, and may be integrally formed with the doorframe 43 forming the main door 40. The shaft installation part 438 maybe formed to form a space in which the hinge shaft 5121 is inserted, andto be rotated while a rotating shaft is inserted into the shaftinstallation part 438.

And when the sub-door 50 is rotated to be opened while the upper hinge51 is coupled to the main door 40, the upper hinge 51 is also rotatedwith rotation of the sub-door 50. At this point, a side end of the hingehole 433 is inserted into the cut-away part 5122 of the upper hinge 51,and thus interference may be prevented.

Due to such a structure of the upper hinge 51, the sub-door 50 may berotatably disposed inside the opening part 403 of the main door 40 whilethe sub-door 50 is closed. And the upper hinge 51 extends laterally, andis rotatably coupled to the inside of the main door 40, and thus theinterference of the upper hinge 51 is prevented while the sub-door 50 isclosed. Therefore, an outer surface of the sub-door 50 and an innersurface of the opening part 403 may be formed to be in close contactwith each other, and thus even when the sub-door 50 is rotated, thesub-door 50 is not sagged or deformed by a stable supporting structureof the upper hinge 51.

And the electric wire L introduced through the electric wire guide part5714 of the upper cap decoration 57 may pass through the hinge hole 433via the hinge shielding part 532 of the hinge cover 53, and may beguided to the inside of the main door 40. Therefore, even while thesub-door 50 is being rotated, the electric wire L is not exposed to theoutside, and is guided to the inside of the main door 40 while beingshielded by the hinge cover 53.

FIG. 29 is a longitudinal cross-sectional view illustrating a couplingstructure of the sub-door and the lower hinge.

As illustrated in the drawing, the lower hinge 52 has the same structureas that of the upper hinge 51, except a bending direction which is bentupward. To install the lower hinge 52, the lower hinge installation part581 may be formed at the lower cap decoration 58 to be recessed, and thelower hinge 52 may be installed and fixed to the lower hingeinstallation part 581 and the hinge insertion part 552 of the first sideframe 55. That is, the lower hinge 52 has a structure which is installedand fixed to a corner of the lower end of the sub-door 50.

In some cases, each of the upper hinge 51 and the lower hinge 52 has astructure which is inserted and fixed by the first side frame 55. Due toa property of the first side frame 55 formed of the metallic material,the first side frame 55 may stably support the upper hinge 51 and thelower hinge 52, and may stably fix the sub-door 50 without the saggingor the deformation of the sub-door 50 even in an environment in whichthe load is applied. Accordingly, a space between the sub-door 50 andthe main door 40 may be designed and maintained to be very narrow, andthus the external appearance may be enhanced.

The lower hinge 52 and may include a door installation part 521 which isinstalled and fixed to the lower hinge installation part 581 by a screw,and a rotary coupling part 522 which is rotatably coupled to the maindoor 40.

The door installation part 521 may include a horizontal part 5211 whichis fixed to the lower hinge installation part 581, and a vertical part5212 which is fixed to the hinge insertion part 552 of the first sideframe 55. And the rotary coupling part 522 may extend from an end of thehorizontal part 5211 so as to pass through the hinge hole 433 of themain door 40, and a hinge shaft 5221 may be formed at one extending end.

The hinge shaft 5221 may be inserted into a shaft installation part 439formed inside the main door 40, and thus the lower hinge 52 may berotatably coupled. And a cut-away part 5222 may be formed at the rotarycoupling part 522 so that one side end of the hinge hole 433 is insertedtherein when the sub-door 50 is rotated. And a stopper 5224 whichrestricts rotation of the sub-door 50 may be further formed at therotary coupling part 522.

In a similar manner, the sub-door 50 may be rotatably installed at themain door 40 by the upper hinge 51 and the lower hinge 52 which extendlaterally from upper and lower ends of one side surface thereof. Thesub-door 50 which has a relatively heavy weight due to the providedpanel assembly 54 may be stably fixed to the inside of the opening part403.

FIG. 30 is an exploded perspective view illustrating a couplingstructure of the knock detection device and the second detection deviceof the sub-door when being seen from a front. And FIG. 31 is an explodedperspective view illustrating a coupling structure of the knockdetection device and the second detection device of the sub-door whenbeing seen from a lower side.

As illustrated in the drawings, the second detection device 81 and theknock detection device 82 may be provided at the lower end of thesub-door 50. The second detection device 81 serves to detect a user'sposition, and to check whether the user stands in front of therefrigerator 1 to operate the refrigerator 1.

The second detection device 81 may be located on an extension line ofthe first detection device 31, and may be arranged vertically with thefirst detection device 31. And an installation height of the seconddetection device 81 corresponds to the lower end of the sub-door 50, andthus an ordinary adult may be detected, but a child having a smallheight, an animal, or other things smaller than the height of the seconddetection device 81 may not be detected.

And the knock detection device 82 may be formed to recognize whether theuser knocks on the front panel 541 of the sub-door 50. A certainoperation of the refrigerator 1 may be designated by a knockingoperation detected by the knock detection device 82. For example, thedoor lighting unit 49 may be turned on by the user's knocking operation,and thus the sub-door 50 may become transparent.

A specific structure of the second detection device 81 and the knockdetection device 82 will be described below in detail.

The lower hinge 52 may be installed at the lower cap decoration 58 whichforms the lower surface of the sub-door 50, and the detection deviceaccommodation part 582 may be formed at one side which is distant fromthe lower hinge 52, i.e., one side which is close to the second sideframe 56 so as to be recessed.

The detection device accommodation part 582 may be formed to have a sizewhich accommodates the second detection device 81 and the knockdetection device 82. And an opened lower surface of the detection deviceaccommodation part 582 may be shielded by the accommodation part cover583.

The case fixing part 481 to which a screw for fixing the accommodationpart cover 583 to the lower cap decoration 58 is fastened may be formedat one side of the accommodation part cover 583. An injection port coverpart 5831 is further formed at the other side of the accommodation partcover 583. The injection port cover part 5831 may be formed on the lowercap decoration 58, and also formed to shield a first injection port 5824through which the foaming solution filled to mold an insulation 501 isinjected. And a plurality of hook parts 5832 are formed at an uppersurface of the injection port cover part 5831 to be fitted into thefirst injection port 5824. Therefore, the injection port cover part 5831is fitted into the first injection port 5824, and the case fixing part481 is fixed to the lower cap decoration 58 by fastening the screw, andthe entire accommodation part cover 583 is installed and fixed to thelower cap decoration 58.

When the accommodation part cover 583 is installed at the lower capdecoration 58, the detection device accommodation part 582 may beshielded, and the first injection port 5824 may also be shielded.

And a PCB installation part 5833 may further be formed at theaccommodation part cover 583. A detection device PCB 83 for processing asignal of the second detection device 81 and the knock detection device82 is installed at the PCB installation part 5833. The detection devicePCB 83 is connected to the second detection device 81 and/or the knockdetection device 82, and may be seated at the PCB installation part5833.

The detection device PCB 83 can serve to process the signal of thesecond detection device 81 and/or the knock detection device 82, and islocated at a position close to the second detection device 81 and theknock detection device 82, and configured to process the signals.

In the case in which the detection device PCB 83 for processing thesignal is located at a distance, there may be a problem that noisegenerated when the signal to be processed is transferred through asignal line may be increased. However, since the detection device PCB 83is located at a position at which the second detection device 81 and theknock detection device 82 are installed, a main control part 2 receivesonly a valid knock-on signal. Accordingly, the noise due to the signalline between the main control part 2 and the detection device PCB 83 maybe minimized. That is, the main control part 2 may receive the signal ofwhich the noise is minimized through the detection device PCB 83.Therefore, it may be possible to ensure an accurate recognition rate.

In particular, in the case of the knock detection device 82, a signaloutput through a microphone 8211 is indicated by mV unit, but the maincontrol part 2 which controls an entire operation of the refrigerator 1generally receives a signal which is basically indicated by V unit.Therefore, due to a scale difference in a physical signal, it is notpreferable that the main control part 2 determines whether the knock-onsignal is normal.

The refrigerator 1 is an electronic appliance using a high voltage/ahigh current. Therefore, an electrical noise generation amount isrelatively great. This means that the signal of mV unit output from themicrophone 8211 may be further vulnerable to the electrical noise.

Therefore, since the detection device PCB 83 is located close to theknock detection device 82, the noise may be remarkably reduced, and thusthe recognition rate may be enhanced.

In some cases, a second injection port 584 through which the foamingsolution is injected may further be formed at one side of the lower capdecoration 58 close to the lower hinge 52. The second injection port 584may be shielded by a separate injection port cover 5841. And a pluralityof hook parts 5842 are formed at an upper surface of the injection portcover 5841 to be fitted into the second injection port 584.

A first boss 5821 to which a screw for fixing the second detectiondevice 81 is fastened, and a second boss 5822 for fixing the knockdetection device 82 are respectively formed at a bottom surface of thedetection device accommodation part 582.

And an electric wire hole 5823 may be formed at one surface of thedetection device accommodation part 582. The electric wire L which isconnected to the detection device PCB 83, the second detection device 81and the knock detection device 82 may be guided to the outside of thesub-door 50 through the electric wire hole 5823.

In some cases, a through part (or opening) 5825 which is opened so thatthe second detection device 81 and the knock detection device 82 are inclose contact with the front panel 541 may be formed at a front surfaceof the detection device accommodation part 582 which is in contact withthe front panel 541.

FIG. 32 is an exploded perspective view of the knock detection device.And FIG. 33 is a cross-sectional view taken along line 33-33′ of FIG. 17. And FIG. 34 is a cross-sectional view of a microphone module of theknock detection device.

A structure of the knock detection device 82 will be described in detailwith reference to the drawings. The knock detection device 82 mayinclude a microphone module 821 which detects the knock-on signal, aholder 823 which accommodates the microphone module 821, an elasticmember 824 which presses the holder 823 and the microphone module 821toward the front panel 541 so that the holder 823 and the microphonemodule 821 are in close contact with the front panel 541, and a supportmember 825 which supports the elastic member 824 and the holder 823.

The microphone module 821 can include the microphone 8211 which directlysenses a sound wave, and a microphone accommodation part (or microphoneaccommodation housing) 8212 which accommodates the microphone 8211. Themicrophone 8211 serves to directly sense the sound wave, may be formedin a circular shape having a predetermined thickness, and installed andfixed into the microphone module 821. One surface of the microphone 8211may be referred to as a sound wave receiving part 8213 which receivesthe sound wave, and the sound wave receiving part 8213 is disposedtoward an opening 8214 of the microphone accommodation part 8212. Andthe other side of the microphone 8211 may be connected to a signal line8216, and the signal line 8216 may also be connected to the detectiondevice PCB 83.

The microphone accommodation part 8212 may be formed of an elasticmaterial such as rubber, and also formed to be in close contact with thefront panel 541. To this end, the opening 8214 may be formed at one sideof the microphone accommodation part 8212 close to the microphone 8211installed in the microphone accommodation part 8212, and a circularprotrusion 8215 may be formed at a circumference of the opening 8214.And the protrusion 8215 serves to enable the microphone accommodationpart 8212 not to be inclined in one direction when the microphoneaccommodation part 8212 is in close contact with the front panel 541,and also to enable an entire opened front surface of the opening part403 to be maintained in a closely contacting state with the front panel541.

A predetermined sealed space may be formed between the opening 8214 andthe sound wave receiving part 8213 which are in close contact with eachother by the protrusion 8215. Therefore, a front of the closelycontacting space is sealed by a medium, i.e., the front panel 541.Accordingly, vibration transmitted through an inside of the mediumvibrates air in the predetermined space, and the sound wave due to thevibration may be received by the microphone 8211.

Due to such a sealing process, introduction of external noise orvibration into the predetermined space may be minimized. Thus, an errorin determining a knocking operation or a malfunction due to the externalnoise may be considerably reduced, and a very accurate recognition ratemay be ensured. That is, accuracy in determining the knocking operationwhen a knock-on input is applied may be remarkably increased.

A module seating part 8231 in which the microphone module 821 isaccommodated and which is opened toward the front panel 541 may beformed at the holder 823. The microphone module 821 may be formed sothat at least the protrusion 8215 protrudes further than a front surfaceof the holder 823 while the microphone module 821 is seated on themodule seating part 8231.

A holder slot 8232 through which the signal line connected to themicrophone 8211 passes may be formed at the holder 823. The holder slot8232 may be formed to be opened at one side of the module seating part8231.

Also, a first elastic member fixing part 8233 which protrudes so thatthe elastic member 824 is installed and fixed thereto may be formed at arear surface of the holder 823. The first elastic member fixing part8233 may be formed to extend and to pass through one end of the elasticmember 824 having a coil shape.

A holder coupling part 8234 which may be formed in a hook shape andcoupled to the support member 825 may be formed at both sides of theholder 823. Due to the holder coupling part 8234, the holder 823 iscoupled so as not to be separated by the support member 825. And also,due to the hook shape of the holder coupling part 8234, movement of theholder 823 in a direction which is inserted into the support member 825is not restricted.

A front surface of the support member 825 may be formed to be opened,and also formed so that the holder 823 is inserted through the openedfront surface thereof. And a second elastic member fixing part 8251which protrudes so that the elastic member 824 is installed and fixedthereto may be formed at an inside of the holder 823. The second elasticmember fixing part 8251 may be located on an extension line of the firstelastic member fixing part 8233, and may be inserted so as to passthrough one end of the elastic member 824.

Therefore, even though the elastic member 824 is compressed to press theholder 823, the elastic member 824 may stably press the holder 823toward the front panel 541 without being buckled.

By the elastic member 824, the microphone module 821 may be maintainedin a closely contacting state with the front panel 541, andparticularly, may be always maintained in the closely contacting statewith the front panel 541 without a position change of the microphonemodule 821 due to a shock generated when the main door 40 and thesub-door 50 are closed and opened or an inertial force generated whenthe main door 40 and the sub-door 50 are rotated.

A support member slot 8252 may be formed at one side of the supportmember 825. The support member slot 8252 may be formed on an extensionline of the holder slot 8232. Therefore, the signal line passing throughthe holder slot 8232 may pass through the support member slot 8252, andmay be connected to the detection device PCB 83.

A support member fixing part 8253 may be formed at the other side of thesupport member 825. The support member fixing part 8253 extends outward,and is seated in the second boss 5822 which protrudes from the detectiondevice accommodation part 582. And the screw passes through a screw hole8254 of the support member fixing part 8253, and is fastened to thesecond boss 5822, and the support member 825 is installed and fixed onthe lower cap decoration 58.

In some cases, the knock detection device 82 may be installed at thearea of the bezel 5411 of the front panel 541, and thus the knockdetection device 82 is not exposed to the outside when being seen froman outside of the front panel 541.

The knock detection device 82 may be located at an edge of the frontpanel 541, but an effective input part for the user's knocking operationis not limited thereto. In a state in which the knock detection device82 is in close contact with the medium, even though the knockingoperation is applied to any positions, the sound wave may be transmittedthrough the continuous same medium due to a property of the microphone8211 which detects the sound wave generated by the vibration, instead ofthe vibration itself, and thus may be effectively detected. Therefore, aposition of the knock detection device 82 may be disposed at one end atwhich the electric wires may be arranged and a visible area of thesub-door 50 may also be maximized. At the same time, even though theuser knocks on any point of the front panel 541, the sound wave may bedetected through the microphone 8211 which is in close contact with thesame medium.

Specifically, an area to which a user's knocking input is applied may bean entire area which is defined by the front surface of the front panel541. Most of the front panel 541 except a boundary portion thereof issubstantially a see-through area which selectively becomes transparent,and the knock detection device 82 may not be disposed thereat.

Therefore, it is preferable that the knock detection device 82 belocated at the area of the bezel 5411 in the front panel 541. Inparticular, the bezel 5411 located at an upper end and left and rightsides of the front panel 541 may be minimized by locating the knockdetection device 82 at the lower end of the front panel 541 rather thanboth of the left and right sides thereof. By such a shape of the bezel5411, the see-through area may be expanded. Since the knock detectiondevice 82 is located at the lower end of the front panel 541 on which auser's eyes are relatively less focused, the wider see-through area maybe provided to the user.

Since the knock detection device 82 is located at the area of the bezel5411, is not exposed to an outside, and has a structure which is inclose contact with the front panel 541, the user's knocking operationmay be detected even though the user knocks on any position of the frontpanel 541.

In some cases, there may be environmental factors other than theknocking operation in which the vibrations are exerted on the frontsurface of the front panel 541. The front surface of the panel assembly54 may be vibrated by the shock generated when the main door 40 and thesub-door 50 are opened and closed, an external loud noise or the like,and such an input due to the external environments may be recognized asa knock signal.

Therefore, the detection device PCB 83 may be set so that a user'soperation which knocks several times the front surface of the sub-door50 may be recognized as a normal knock input. More specifically, theuser's operation which knocks several times the front surface of thesub-door 50 at predetermined time intervals may be recognized as thenormal knock input.

For example, when the user knocks twice the front surface of thesub-door 50 within a predetermined time, it may be recognized as thenormal knock input. When a general user's knock pattern is analyzed, itmay be understood that a time interval between a first knock and asecond knock is less than about 600 ms. That is, when it is consideredthat 1 second (s) is 100 ms, a case in which the first knock and thesecond knock are performed at a time interval less than 1 second may berecognized as the normal knock input.

Therefore, by setting the time interval, an abnormal input may beremarkably prevented from being misrecognized as the knock signal.

In some cases, there may be a deviation in a knock intensity accordingto the user. However, since the medium is the same, it may be understoodthat the deviation in the knock intensity may be large, but a deviationin a vibration pattern is very small. Therefore, the deviation in theknock intensity may be offset through an algorithm, and the normal knockinput may be effectively recognized using a knock input pattern and thetime interval between the knocks as factors.

FIG. 35 is an exploded perspective view illustrating a couplingstructure of the second detection device. And FIG. 36 is a partialperspective view illustrating an installed state of the second detectiondevice.

As illustrated in the drawings, the second detection device 81 may belocated inside the detection device accommodation part 582, and may belocated at a lateral side of the knock detection device 82.

The second detection device 81 is a device which detects a user'sapproach, and a position sensing device (PSD) may be used as the seconddetection device 81. That is, the second detection device 81 includes alight emitting part 811 and a light receiving part 812, and may beformed so that the infrared light is emitted from the light emittingpart 811, an angle of the reflected light is measured by the lightreceiving part 812, and thus a position of the user is recognized. Anapproach distance which is detected by the PSD may be set, and adetectable distance of the second detection device 81 is set to lessthan 1 m, and thus, when the user is located within a distance of 1 mfrom the front surface of the refrigerator 1, it may be recognized thatthe user is located in front of the refrigerator 1 to operate therefrigerator 1.

Like the knock detection device 82, an installation position of thesecond detection device 81 corresponds to the lower end of the sub-door50 located at an upper side. Since the installation position correspondsto a height of about 1 m from a floor, the child having the small heightor other things having the low height may not be detected.

A pressing member 813 may be further provided at a rear of the seconddetection device 81. The pressing member 813 may be formed to press thesecond detection device 81 so that the second detection device 81 isinstalled and fixed to the detection device accommodation part 582, andalso the second detection device 81 is in close contact with the frontpanel 541.

Specifically, a detection device fixing part 8131 which is fixed to arear surface of the second detection device 81 may be formed at thepressing member 813. The detection device fixing part 8131 is coupled toboth side ends of the second detection device 81, and thus the pressingmember 813 and the second detection device 81 may be integrally coupledto each other.

And an elastic part 8132 which protrudes backward to be rounded may beformed between the detection device fixing parts 8131. The elastic part8132 may be elastically deformed by a pressure, and an end of theelastic part 8132 which protrudes while the second detection device 81is installed may be in close contact with a wall surface of thedetection device accommodation part 582, and elastically deformed.Therefore, the second detection device 81 may be in close contact withthe front panel 541 by an elastic restoring force of the elastic part8132. Therefore, the light emitting part 811 and the light receivingpart 812 may be completely in close contact with the rear surface of thefront panel 541.

The front surface of the second detection device 81 may pass through thethrough part 5825 formed at the front surface of the detection deviceaccommodation part 582, and may be disposed at an area of thepenetration part 5412 which may be formed at the bezel 5411 to betransparent.

Therefore, the second detection device 81 has a structure which isactually exposed to the outside through the penetration part 5412.However, the second detection device 81 may have a black color or a darkgray color which is the same as or similar to a color of the front panel541 having a half mirror structure, and thus may not be easily seen whenbeing seen from an outside.

That is, the light emitted from the second detection device 81 does notinterfere with the bezel 5411, and the second detection device 81 isprevented from being remarkably exposed, and thus the externalappearance is also prevented from being degraded.

In some cases, a pressing member fixing part 8133 may be formed at oneside of the pressing member 813. The pressing member fixing part 8133may be formed to extend outward, and seated at the first boss 5821 whichprotrudes from the detection device accommodation part 582. And thescrew passing through a screw hole 8134 of the pressing member fixingpart 8133 is fastened to the first boss 5821, and thus the pressingmember 813 is installed and fixed on the lower cap decoration 58.

FIG. 37 is a view illustrating an electric wire arrangement inside thesub-door.

As illustrated in the drawing, in the sub-door 50, while the seconddetection device 81 and the knock detection device 82 are assembled, thedetection device accommodation part 582 is shielded by the accommodationpart cover 583. At this point, the detection device PCB 83 is installedat an inner surface of the accommodation part cover 583, and theelectric wire L which is connected to the second detection device 81,the knock detection device 82 and the detection device accommodationpart 582 is guided to an outside of the detection device accommodationpart 582 through the electric wire hole 5823.

In the sub-door 50, a space in which the insulation 501 is formed may beprovided at an outer perimeter of the panel assembly 54, i.e., aninternal area of the upper cap decoration 57, the lower cap decoration58, the first side frame 55 and the second side frame 56.

Therefore, an empty space may be formed before the foaming solution formolding the insulation 501 is injected, and the electric wire L passingthrough the electric wire hole 5823 of the detection deviceaccommodation part 582 may be guided along a space formed by the secondside frame 56 and the upper cap decoration 57.

And the electric wire L guided to the upper hinge installation part 571through the electric wire hole 5713 of the upper hinge installation part571 may be covered by the hinge cover 53. And the electric wire L isguided to the inside of the main door 40 through a space between thehinge cover 53 and the upper hinge 51, and is not exposed to the outsideeven while the sub-door 50 is being rotated.

In some cases, the first injection port 5824 and the second injectionport 584 are formed at the lower cap decoration 58, and may be shieldedby the injection port cover 5841 and the injection port cover part 5831formed at the accommodation part cover 583.

The first injection port 5824 may be located at a lateral side of thedetection device accommodation part 582, and may be located at aposition close to the second side frame 56. The first injection port5824 may be formed as outward as possible. When the first injection port5824 may be formed at a position which is at least partially overlappedwith a space between the panel assembly 54 and the second side frame 56,it is easy to inject the foaming solution between the panel assembly 54and the second side frame 56. However, since the inference may occur dueto a shape of the handle 561 formed at the second side frame 56, it ispreferable that first injection port 5824 may be formed as outward aspossible.

A foaming solution guide part 585 which may be formed inside the firstinjection port 5824 to be rounded toward the second side frame 56 may beformed inside the lower cap decoration 58. Therefore, when the foamingsolution is injected through the first injection port 5824, the foamingsolution may naturally flow to the space between the second side frame56 and the panel assembly 54.

The second injection port 584 may be formed on the lower cap decoration58 close to the lower hinge installation part 581. The second injectionport 584 is located to avoid the interference with the lower hingeinstallation part 581. At this point, the second injection port 584 maybe formed at a position which is spaced laterally further than a spaceformed by the first side frame 55 and the panel assembly 54.

A width of the space between the first side frame 55 and the panelassembly 54 is narrow, and thus the foaming solution may overflow whenthe foaming solution is directly injected. To solve the problem, thefoaming solution may primarily be injected into a relatively wide spaceformed by the lower cap decoration 58 and the panel assembly 54, whereit can then naturally flow to the space formed by the first side frame55 and the panel assembly 54.

There may be a difference in fluidity of the foaming solution accordingto positions of the first injection port 5824 and the second injectionport 584. The foaming solution may be simultaneously injected at both ofthe first injection port 5824 and the second injection port 584, and maybe filled at the perimeter of the sub-door 50.

FIG. 38 is a perspective view illustrating a state in which the foamingsolution is injected into the sub-door. And FIG. 39 is a viewillustrating an arrangement of a vent hole of the sub-door.

Referring to the drawings, in a state in which the accommodation partcover 583 and the injection port cover 5841 are opened, the foamingsolution is injected toward the first injection port 5824 and the secondinjection port 584. At this point, a pressure of the foaming solutioninjected to each of the first injection port 5824 and the secondinjection port 584 may be set differently. That is, the foaming solutionwhich is injected to the first injection port 5824 having a relativelywide flowing space may be injected at a relatively high pressure.

A flowing path of the foaming solution will be described with referenceto FIG. 38 . The foaming solution injected to the first injection port5824 is introduced into a space formed by the second side frame 56 andthe panel assembly 54 through the foaming solution guide part 585. Then,the foaming solution flows continuously to a space formed by the uppercap decoration 57 and the panel assembly 54.

The foaming solution injected to the second injection port 584 is firstinjected into the space formed by the lower cap decoration 58 and thepanel assembly 54, and then flows continuously to the space between thefirst side frame 55 and the panel assembly 54.

The foaming solution which is simultaneously injected to both of thefirst injection port 5824 and the second injection port 584 is combinedat an area A of the upper cap decoration 57 or an area B of the firstside frame 55. Then, the foaming solution is fully filled in a spaceformed by the upper cap decoration 57, the first side frame 55 and thesecond side frame 56, and then finally filled in the space formed by thelower cap decoration 58 and the panel assembly 54. After the filling ofthe foaming solution is completed, the first injection port 5824 and thesecond injection port 584 are shielded by the accommodation part cover583 and the injection port cover 5841.

Meanwhile, a vent hole 5921 through which air remaining in the sub-door50 is discharged when the foaming solution is injected may be formed atthe sub-door liner 59. The vent hole 5921 may be formed at a gasketinstallation groove 592 at which the sub-door gasket 591 formed alongthe sub-door liner 59 is installed.

The gasket installation groove 592 may be formed to be recessed along aperimeter of the sub-door liner 59, and the vent hole 5921 may be formedin the gasket installation groove 592 at regular intervals. And afterthe foaming solution is fully filled, the sub-door gasket 591 isinstalled at the gasket installation groove 592. Therefore, the venthole 5921 may be covered by the sub-door gasket 591, and may not beexposed to an outside.

Meanwhile, the vent hole 5921 may be formed at a partial section of theentire gasket installation groove 592. The vent hole 5921 may be formedat regular intervals along areas A and B at which the upper capdecoration 57 and the first side frame 55 are disposed, andparticularly, may be formed at regular intervals based on a corner atwhich the upper cap decoration 57 and the first side frame 55 meet.

Therefore, the air in the sub-door 50 may be discharged at an area closeto a point at which the foaming solutions injected into the firstinjection port 5824 and the second injection port 584 are combined. Theair may be continuously discharged until the foaming solution iscompletely filled.

FIG. 40 is a perspective view illustrating an operation state of aprojector of the refrigerator. And FIG. 41 is a cut-away perspectiveview illustrating an internal structure of a freezer compartment of therefrigerator.

As illustrated in the drawings, the freezer compartment 13 may be openedand closed by one pair of the freezer compartment doors 30. And thefirst detection device 31 and a projector 32 may be provided at a rightone (in FIG. 40 ) of the pair of freezer compartment doors 30.

It is preferable that the first detection device 31 and the projector 32are provided at the right one of the pair of freezer compartment doors30 at which the sub-door 50 is located. And the first detection device31 may be vertically disposed on an extension line of the seconddetection device 81.

An inclined surface 331 which is formed to be inclined downward towardan inside may be formed at a lower portion of the freezer compartmentdoor 30. And the first detection device 31 and the projector 32 may beprovided at the inclined surface 331.

The projector 32 serves to project light on a floor surface located infront of the refrigerator 1. An image P such as a design and a charactermay be projected through the projector 32. For example, when theprojector 32 is turned on, the image P including a word like “Door open”may be displayed on the floor surface located in front of therefrigerator 1.

Meanwhile, the first detection device 31 may be disposed at a lower sideof the projector 32. The projector 32 and the first detection device 31may be formed in one module, and may be installed together at theinclined surface 331.

The first detection device 31 may be configured with a kind of proximitysensor which detects a position, and may be provided at the lower sideof the projector 32, and may detect whether an object is located at aposition of the image P projected by the projector 32.

That is, when the user locates his/her body like a foot on the image Pprojected by the projector 32, the first detection device 31 may detectthe body. A PSD sensor or an ultrasonic sensor may be used as the firstdetection device 31, and various kinds of proximity sensors whichrecognize a distance of about 10 to 20 cm may be used.

The projector 32 and the first detection device 31 may be installed onthe inclined surface 331 to project the image right in front of therefrigerator 1 or at a lower side of the inclined surface 331 and todetect the object. Therefore, an erroneous detection is prevented fromoccurring due to a person or an animal which just passes by therefrigerator 1, an object which performs a cleaning operation or thelike. That is, the user stands at a position close to the refrigerator 1to be detected by the first detection device 31. At this point, when theuser's foot is located right in front of the inclined surface 331 or atthe lower side of the inclined surface 331, the foot is detected by thefirst detection device 31.

Detecting of the first detection device 31 may include a motion ofcovering at least a part of the image P projected by the projector 32for a preset time, a motion of passing through an area of the image P,and another motion which may be recognized by the first detection device31.

In addition, it may be set that positioning of the user is recognized asan user's operation for operating the refrigerator 1 only when thepositioning is simultaneously detected by a combination of the firstdetection device 31 and the second detection device 81, and thusmalfunction may be minimized. To this end, when the user is detected bythe second detection device 81, the projector 32 may be operated, and adetection value of the first detection device 31 may be valid.

Like this, when both of the first detection device 31 and the seconddetection device 81 validly perform an detection operation, the dooropening device 70 may be operated to open the main door 40. Theimplementation of the present disclosure has described an example inwhich the main door 40 is opened by the door opening device 70. However,the sub-door 50 or the freezer compartment door 30 may be openedaccording to a position of the door opening device 70.

Meanwhile, the user may grip a freezer compartment handle, and then mayrotate the freezer compartment door 30, and thus the freezer compartment13 may be opened and closed by rotation of the freezer compartment door30. An opening and closing detection device 302 may be provided at afreezer compartment door hinge 301 which rotatably supports the freezercompartment door 30, and whether or not the freezer compartment door 30is opened may be determined by the opening and closing detection device302.

And when the freezer compartment door 30 is opened at a preset angle ormore, and the freezer compartment accommodation member 131 providedinside the freezer compartment door 30 is in a state which may bewithdrawn, the freezer compartment accommodation member 131 may beautomatically withdrawn forward by driving of an accommodation memberwithdrawing device 34.

To this end, the freezer compartment accommodation member 131 having adrawer or basket shape may be supported by a sliding rail 1311 so as tobe inserted into or withdrawn from the freezer compartment 13. And theaccommodation member withdrawing device 34 provided inside the freezercompartment 13 may be formed so that an inserting and withdrawing rod341 is inserted and withdrawn by driving of a motor and a gear assembly.

The inserting and withdrawing rod 341 may be connected to the freezercompartment accommodation member 131, and thus the freezer compartmentaccommodation member 131 may be automatically withdrawn by driving ofthe accommodation member withdrawing device 34. At this time, even whena plurality of freezer compartment accommodation members 131 areprovided, the inserting and withdrawing rod 341 may be connected to allof the plurality of freezer compartment accommodation members 131through a connection member 342, and thus the plurality of freezercompartment accommodation members 131 may be inserted and withdrawn atthe same time.

When the freezer compartment door 30 is rotated to be closed, and thenit is determined that the freezer compartment door 30 is rotated at apredetermined angle or more before being in contact with the freezercompartment accommodation member 131, the accommodation memberwithdrawing device 34 is reversely rotated, and the inserting andwithdrawing rod 341 is inserted, and thus the freezer compartmentaccommodation member 131 may be slid and inserted to an initialposition.

Hereinafter, an operation of the sub-door of the refrigerator accordingto the implementation of the present disclosure having theabove-described structure will be described.

FIG. 42 is a block diagram illustrating a flow of a control signal ofthe refrigerator. And FIG. 43 is a flowchart sequentially illustratingan operation of the sub-door of the refrigerator.

As illustrated in the drawings, the refrigerator 1 includes the maincontrol part 2 which controls the operation of the refrigerator 1, andthe main control part 2 may be connected to a door switch 21. The doorswitch 21 may be provided at the cabinet 10, and may detect opening ofthe refrigerator compartment door 20 or the main door 40, and may alsobe provided at the main door 40, and may detect opening of the sub-door50.

And the main control part 2 may be connected to the main lighting unit85 provided inside the cabinet 10, and may illuminate the inside of therefrigerator 1 when the refrigerator compartment door 20 or the maindoor 40 is opened. And the main control part 2 may be connected to thedoor lighting unit 49, and may enable the door lighting unit 49 to beturned on when the sub-door 50 is opened or the knock-on signal isinput.

And the main control part 2 may be connected to the display unit 60, andmay control an operation of the display unit 60, and may receive anoperating signal through the display unit 60. Also, the main controlpart 2 may be connected to the door opening device 70 and theaccommodation member withdrawing device 34, and may control operationsof the door opening device 70 and the accommodation member withdrawingdevice 34.

The main control part 2 may be connected to a communication module 84.The communication module 84 serves to transmit and receive data such asstate information of the refrigerator 1, program updating, andtransmitting of a using pattern, and may be configured with a devicewhich allows short range communication such as NFC, WiFi and Bluetooth.And setting of the communication module 84 may be performed at thedisplay unit 60.

The main control part 2 may be directly or indirectly connected to thefirst detection device 31, the second detection device 81, the knockdetection device 82 and the projector 32, and may receive the operatingsignals thereof or may control the operations thereof. And when thedetection device PCB 83 is connected to the knock detection device 82and/or the first detection device 31, the detection device PCB 83 may beconnected to the main control part 2. And the knock detection device 82and the detection device PCB 83 may be integrally formed with eachother.

In a general state in which a separate operation is not applied to therefrigerator 1 having the above-described configuration, the sub-door 50is in the opaque state like the mirror surface, as illustrated in FIG. 4. In this state, it may not be possible to see through the inside of therefrigerator 1.

And in this state, the first detection device 31, the second detectiondevice 81 and the knock detection device 82 are maintained in anactivated state in which the user may input the operation anytime[S110].

In this state, when the user locates in front of the front surface ofthe refrigerator 1 to open the main door 40 or the sub-door 50 of therefrigerator 1, the second detection device 81 detects the user'sposition. At this time, when the user is not an ordinary adult, but achild, the user may not be detected due to a property of the position ofthe second detection device 81. When a height of an object which isbeing cleaning or traveling is lower than that of the second detectiondevice 81, the object may not be detected, and thus the malfunction maybe prevented. Meanwhile, the detecting of the second detection device 81is not essential, and thus may be selectively set by the user'soperation [S120].

Then, when the user performs a knocking operation which knocks on thefront surface of the sub-door 50, i.e., the front panel 541, the knockdetection device 82 may detect the knocking operation, and the detectiondevice PCB 83 determines whether the knocking operation is valid.

Specifically, when the user knocks on the front panel 541, the soundwave due to the vibration generated at this point is transmitted alongthe front panel 541 formed of the same medium, and the microphone 8211which is in close contact with the front panel 541 receives the soundwave.

The received sound wave is filtered and amplified while passing througha filter and an amplifier, and transmitted to the detection device PCB83. The detection device PCB 83 determines the knock with the signalwhich is collected and analyzed to detect the knock signal.

That is, in the case of the sound wave which is generated by a noise ora shock inside or outside the refrigerator 1, there is a difference fromthe sound wave generated by the knocking operation in a propertythereof, and thus the detection device PCB 83 determines whether theuser performs the knocking operation through the signal corresponding tothe property of the knock signal.

Of course, in a certain situation, a signal similar to the knock signalmay be generated, or a shock similar to the knock may be applied to thefront panel 541 due to the user's carelessness or inexperiencedoperation, or the external noise may be recognized as a signal similarto a wavelength of the knock signal.

To prevent misrecognition in the certain situation, the detection devicePCB 83 can confirm whether the knock signal is continuously generated ina preset pattern, and also determines whether the pattern may be formedwithin a preset time.

For example, it may be set that, when a signal which is recognized asthe knock is generated twice within one second, the signal may bedetected as the valid knock-on signal. In an analysis of the generaluser's knock pattern, when the knock is performed continuously twice,the time interval is less than one second. Therefore, when a signalrecognition condition is set as described above, the misrecognition inthe certain situation may be prevented, and also the user's knockingoperation may be accurately recognized. Of course, the number of theknock signal and the set time necessary to be recognized as the validknock-on signal may be changed variously.

When a detecting signal is not detected by the second detection device81, or it is determined through the knock detection device 82 that thevalid knock-on signal is not generated, the main control part 2 does notperform a separate control operation, and is maintained in a standbystate.

And while the main door 40 or the sub-door 50 is opened, the seconddetection device 81 and the knock detection device 82 may beinactivated, or may ignore the input signal, and thus the malfunctionmay be prevented [S130].

Meanwhile, when the valid knock-on signal is detected, and the detectiondevice PCB 83 transmits the valid signal to the main control part 2, themain control part 2 turns on the main lighting unit 85 or the doorlighting unit 49.

When the main lighting unit 85 or the door lighting unit 49 is turnedon, the inside of the refrigerator 1 becomes bright, and the lightinside the refrigerator 1 passes through the panel assembly 54. Inparticular, when the light passes through the front panel 541, the frontpanel 541 becomes transparent, and thus the inside thereof may be seenthrough, as illustrated in FIG. 5 .

When the sub-door 50 becomes transparent, the user may confirm theaccommodation space inside the main door 40 or the space inside therefrigerator 1, and thus may open the sub-door 50 to store the food, ormay perform a necessary operation.

At this time, the display unit 60 may also be turned on, and may displayoperation information of the refrigerator 1. Therefore, the user maycheck the information output from the display 61 disposed inside themain door 40 through the sub-door 50 [S140].

The turned-on main lighting unit 85 or the door lighting unit 49 may bemaintained in a turned-on state for a preset time, e.g., 10 seconds, andthus may allow the user to sufficiently confirm an internal state of therefrigerator 1. Of course, the display unit 60 may also be maintained ina turned-on state for a preset time.

And it is determined whether the preset time passed while the mainlighting unit 85 or the door lighting unit 49 is turned on. When thepresent time passes, the main lighting unit 85 or the door lighting unit49 is turned off [S150].

And while the main lighting unit 85 or the door lighting unit 49 isturned on, a valid knocking operation signal may be input by the userbefore the preset time passes.

That is, when the user performs the knocking operation to confirm theinside of the refrigerator 1, but a separate operation is not needed,the main lighting unit 85 or the door lighting unit 49 may be turned offbefore the preset time passes.

For example, in a state in which the user confirms an accommodationstate inside the refrigerator 1 within 5 seconds after the main lightingunit 85 or the door lighting unit 49 is turned on, or confirms theinformation displayed on the display unit 60, when it is intended thatthe sub-door 50 becomes opaque, the knocking operation may be performedagain on the front surface of the sub-door 50, i.e., the front panel541.

At this point, when it is determined that the knocking operation isvalid, the main lighting unit 85 or the door lighting unit 49 may beturned off before the preset time passes, and the display unit 60 mayalso terminate an output of the information. Of course, validitydetermination of the knocking operation may be set to be the same as theoperation S130, and in some cases, may be set to another knock inputpattern [S160].

When the preset time passes after the main lighting unit 85 or the doorlighting unit 49 is turned on, or the valid knock-on signal is input,the main lighting unit 85 or the door lighting unit 49 may be turnedoff.

When the main lighting unit 85 or the door lighting unit 49 is turnedoff, the inside of the refrigerator 1 becomes dark, and the outsidethereof is in a bright state. In this state, the light outside therefrigerator 1 is reflected by the front panel 541, and thus the frontsurface of the sub-door 50 is in the mirror-like state, and the user maynot see through the inside thereof. Therefore, the sub-door 50 ismaintained in the opaque state until a new operation is input [S170].

Hereinafter, an operation of the display unit 60 will be described withreference to the drawings.

FIG. 44 is a perspective view illustrating an installed state of thedisplay unit. And FIG. 45 is a view illustrating a configuration of afront surface of the display unit.

As illustrated in the drawings, the display unit 60 is provided at alower end of the opening part 403 of the main door 40. And when the mainlighting unit 85 or the door lighting unit 49 is turned on so that thesub-door 50 becomes transparent, the display unit 60 may also be turnedon together, and thus the user may confirm the information of thedisplay unit 60 through the sub-door 50 even while the sub-door 50 isclosed.

The display unit 60 may be turned on while the sub-door 50 is opened.The user may open the sub-door 50 to operate the display unit 60, andwhen the opening of the sub-door 50 is detected by the door switch 21,the display unit 60 may be activated.

The display 61 may be provided at a center of a front surface of thedisplay unit 60, and the plurality of operating buttons 62 may beprovided at both of left and right sides of the display 61.

The display 61 may be a screen through which the operation informationof the refrigerator 1 is output, and may be selectively turned on andoff according to the knocking operation on the front panel 541 or theopening and closing of the sub-door 50.

The operating buttons 62 serve to set the operation of the refrigerator1, and may include a communication button 621, a lock button 622, anauto-door button 623, an auto-drawer button 624, a refrigeratorcompartment temperature fixing button 625, a freezer compartmenttemperature fixing button 626, an air cleaning button 627, and a quickfreezing button 628. A combination of the operating buttons 62 is justan example for convenience of explanation, and is not limited thereto.

FIG. 46 is a view illustrating a change in a display state of thedisplay unit according to a knocking operation.

As illustrated in the drawing, the display 61 is maintained in an OFFstate until the knocking operation on the front panel 541 is performed.And when the user knocks on the front panel 541, the display 61 isturned on. At this point, a first screen 611 or a second screen 612which outputs a temperature in the refrigerator 1 and a presentoperating function may be output on the display 61.

Since the main lighting unit 85 or the door lighting unit 49 is turnedon, and the sub-door 50 becomes transparent, the information of thedisplay 61 may be indicated even while the sub-door 50 is closed.

When the preset time passes after the display unit 60 is turned on, orthe user knocks again on the front panel 541, the display 61 is turnedoff. At this time, the main lighting unit 85 or the door lighting unit49 is also turned off, and the sub-door 50 is in the opaque state, andthus the display 61 is not visible from the outside.

FIG. 47 is a view illustrating the change in the display state when thesub-door is opened and closed.

As illustrated in the drawing, while the sub-door 50 is closed, thedisplay 61 is turned off. And when the sub-door 50 is opened, theopening of the sub-door 50 is detected by the door switch 21, and themain control part 2 turns on the display 61.

When the display 61 is turned on, the operation information of therefrigerator 1 is displayed on the first screen 611, and the firstscreen 611 is changed into the second screen 612 after the preset timepasses, and another operation information of the refrigerator 1 isdisplayed on the second screen 612. At this point, the informationdisplayed on the first screen 611 and the second screen 612 may be setby the user's operation.

For example, the first screen 611 may display all of the temperatures ofthe refrigerator compartment 12 and the freezer compartment 13, and mayalso the present operating function. And the second screen 612 maydisplay the temperature of one storage space of the refrigeratorcompartment 12 or the freezer compartment 13 and the present operatingfunction in the corresponding storage space.

Meanwhile, when the sub-door 50 is closed, the display 61 can detectclosing of the sub-door 50 by the door switch 21, and the main controlpart 2 turns off the display 61.

FIG. 48 is a view illustrating the change in the display state of thedisplay unit when an auto-door function is set.

As illustrated in the drawing, in a state in which the sub-door 50 isopened and the display 61 is turned on, when the user pushes theauto-door button 623, the display 61 displays a third screen 613 whichindicates an activated state of the door opening device 70 when the dooropening device 70 is activated. And when the door opening device 70 isnot activated, the display 61 displays a fourth screen 614 whichindicates an inactivated state of the door opening device 70.

And when the user operates again the auto-door button 623 while thedisplay 61 displays the third screen 613 or the fourth screen 614, thethird screen 613 and the fourth screen 614 may be converted to eachother, and a state of the door opening device 70 may also besubstantially changed.

That is, when it is intended that the user does not use the door openingdevice 70, it may be set through operating of the auto-door button 623.And in this state, an operation of the door opening device 70 is notperformed.

Meanwhile, when the user's operation is not applied for a preset time ormore in a state in which it is converted to the third screen 613 or thefourth screen 614, the display 61 is converted to the first screen 611or the second screen 612 which indicates the temperature in therefrigerator 1. At this time, when the door opening device 70 isactivated, the auto-door button 623 may be in an ON state, and when thedoor opening device 70 is inactivated, the auto-door button 623 may bein an OFF state.

FIG. 49 is a view illustrating the change in the display state of thedisplay unit when an auto-drawer function is set.

As illustrated in the drawing, when the user pushes the auto-drawerbutton 624 while the sub-door 50 is opened and the display 61 is turnedon, the display 61 displays a fifth screen 615 which indicates anactivated state of the accommodation member withdrawing device 34 whenthe accommodation member withdrawing device 34 is activated. And whenthe accommodation member withdrawing device 34 is inactivated, thedisplay 61 displays a sixth screen 616 which indicates an inactivatedstate of the accommodation member withdrawing device 34.

And when the user operates again the auto-drawer button 624 while thedisplay 61 displays the fifth screen 615 or the sixth screen 616, thefifth screen 615 or the sixth screen 616 may be converted to each other,and a state of the accommodation member withdrawing device 34 may alsobe substantially changed.

That is, when it is intended that the user does not use theaccommodation member withdrawing device 34, it may be set throughoperating of the auto-drawer button 624. And in this state, an operationof the accommodation member withdrawing device 34 is not performed.

Meanwhile, when the user's operation is not applied for a preset time ormore in a state in which it is converted to the fifth screen 615 or thesixth screen 616, the display 61 is converted to the first screen 611 orthe second screen 612 which indicates the temperature in therefrigerator 1. At this time, when the accommodation member withdrawingdevice 34 is activated, the auto-drawer button 624 may be in an ONstate, and when the accommodation member withdrawing device 34 isinactivated, the auto-drawer button 624 may be in an OFF state.

FIG. 50 is a view illustrating the change in the display state of thedisplay unit when the temperature fixing function is set.

As illustrated in the drawing, in a state in which the sub-door 50 isopened and the display 61 is turned on, when the user pushes therefrigerator compartment temperature fixing button 625, the main controlpart 2 may control the operation of the refrigerator 1 so that thetemperature in the refrigerator 1 is maintained at a preset temperature,and a seventh screen 617 which indicates such a state is displayed. Andwhen a refrigerator compartment temperature fixing mode is not set, thedisplay 61 displays an eighth screen 618 which indicates an in activatedstate of the refrigerator compartment temperature fixing mode.

And when the user operates again the refrigerator compartmenttemperature fixing button 625 while the display 61 displays the seventhscreen 617 or the eighth screen 618, the seventh screen 617 or theeighth screen 618 may be converted to each other, and an operation modeof the refrigerator 1 may also be substantially changed.

That is, when it is intended that the user does not use the refrigeratorcompartment temperature fixing mode, it may be set through operating ofthe refrigerator compartment temperature fixing button 625. And in thisstate, an operation of the refrigerator compartment temperature fixingmode is not performed.

Meanwhile, when the user's operation is not applied for a preset time ormore in a state in which it is converted to the seventh screen 617 orthe eighth screen 618, the display 61 is converted to the first screen611 or the second screen 612 which indicates the temperature in therefrigerator 1. At this time, when the refrigerator compartmenttemperature fixing mode is activated, the refrigerator compartmenttemperature fixing button 625 may be in an ON state, and when therefrigerator compartment temperature fixing mode is inactivated, therefrigerator compartment temperature fixing button 625 may be in an OFFstate.

Also, in an operation of the freezer compartment temperature fixingbutton 626, the air cleaning button 627, the quick freezing button 628and the communication button 621, a state of the display 61 is changedin the above-described manner, except contents of the screen, and thusdetailed description thereof will be omitted.

The refrigerator and the control method thereof according to theproposed implementation of the present disclosure have the followingeffects.

In the refrigerator according to the implementation of the presentdisclosure, the panel assembly which selectively transmits or reflectsthe light is provided at a part of the door, and the lighting unit whichis turned on or off by the user's operation is provided inside the door,and the lighting unit can be turned on by the user's operation while thedoor is closed, and thus it may be possible to see through the inside ofthe refrigerator.

Therefore, even while the door is not opened, the user can confirm thespace inside the refrigerator, and also can check the position of thefood, and thus the user convenience can be enhanced. Also, the door canbe prevented from being unnecessarily opened and closed, and loss of thecooling air can be prevented, and thus it may be possible to improvepower consumption and also to enhance storage performance.

And the panel assembly has a structure like a half glass which is seenthrough while the lighting unit is turned on, and functions as a mirrorwhile the lighting unit is not turned on, and thus an exterior of therefrigerator door can be enhanced.

And the microphone which detects a sound generated by the vibration uponthe user's knocking operation on the panel assembly can be provided atthe rear surface of the panel assembly. Therefore, the lighting unit canbe turned on or off by the user's knocking operation, and thus the panelassembly can be selectively transparent.

Therefore, since the panel assembly can become transparent by the simpleoperation, and the sound of the vibration transmitted through the samemedium is the same even though the user knocks on any positions of thefront surface of the panel assembly, the operation can be easilyperformed, and effectively detected.

In some cases, when the panel assembly becomes transparent so that theinside of the panel assembly is visible, the display unit providedinside the refrigerator may be turned on to output an operation state ofthe inside of the refrigerator. Therefore, the user may confirm thedisplay by a knocking operation of the panel assembly.

Therefore, in a state in which the usability for displaying theoperation state of the refrigerator is maintained, the display may notbe seen normally, so that the external appearance may be made simplerand more luxurious.

In some cases, the display unit may have a detachable structure, and adisplay unit of various specifications may be mounted according to amodel or function of the refrigerator. Therefore, various display unitsmay be selectively installed without changing the structure of therefrigerator door.

In some cases, the display unit may output a first screen in a state inwhich the display unit is first turned on, and output a second screen inwhich other information is displayed after the elapse of the set time.Therefore, since various operation states of the refrigerator can beconfirmed through the change of the screen of the display of the insideof the refrigerator while the door is closed without any additionaloperation, improved usability may result.

In some cases, the display unit may be activated when the door isopened, so that the operating button may be operated. And, variousfunctions of the refrigerator may be set by the operation of theoperating button, and the set function may be displayed through thedisplay. User convenience may be further improved as a result.

In some cases, the display PCB of the display unit may be surrounded bya resin material. This way, it may be possible to prevent the displayPCB from being damaged due to humidity or moisture of the inside of therefrigerator.

In some implementations, a display unit may be provided inside therefrigerator at a position corresponding to the panel assembly. Thedisplay unit may become visible when the lighting unit is turned on andmay, for example, display an operation state of the refrigerator.

In some cases, the display unit may be detachably provided in theopening part of the door. For example, display installing protrusionsmay be formed in the opening part, and display guides in which theinstalling protrusions are inserted may be formed on both side surfacesof the display unit. The installing protrusions may be provided on bothside surfaces of the opening part, and the display guides may be openeddownward, so that the installing protrusions may be inserted andmounted.

In some cases, a door connector connected with a main control partcontrolling the operation of the refrigerator may be provided in theopening part, and a display connector electrically connected with thedoor connector may be provided on a lower surface of the display. Thedisplay unit may be seated on a lower end of the opening part, and bothside ends of the display may be detachably coupled to an inner sidesurface of the opening part.

Also, the display unit may include an outer case that forms an outershape and may be detachably coupled to the inside of the refrigerator,an inner case seated inside the outer case and accommodating a displayPCB in which a display and an operating button are disposed, and adisplay cover which is in close contact with a front surface of thedisplay PCB and shielding an opened front surface of the outer case.

Elements mounted on the out display PCB may be formed to be surroundedby a resin material for moisture proofing. The display may be exposed toa center of the display cover, and a plurality of operating buttons maybe disposed on both left and right sides of the display. The displaycover may be formed to be inclined rearward toward an upper portion. Alower end of the display cover may be extended to a positioncorresponding to a rear surface of the sub-door when the sub-door isclosed.

In some cases, a door switch detecting the opening and closing of thesub-door may be provided in the main door, and when the sub-door isopened by the door switch, the display unit may be activated and turnedon. Additionally, after the sub-door is opened, when the door switchdetects that the sub-door is closed, the display unit may be turned off.The display unit may be turned on and off together with the lightingunit.

In some cases, the detection device may be a knock detecting deviceprovided on a rear surface of the panel assembly and detecting aknocking operation of the panel assembly by the user. A bezel that doesnot transmit light may be formed on a rear surface edge of the panelassembly, and the knock detection device may be disposed in an areawithin the bezel.

In some cases, the panel assembly may include a front panel that forms afront surface of the sub-door and formed of a half mirror that reflectsa part of light and transmits a part and selectively becomestransparent, a plurality of insulation panels spaced apart from thefront panel and formed of a transparent tempered glass, and a cudgeldisposed between the front panel and the insulation panel and betweenthe plurality of insulation panels, and separating and sealing betweenthe front panel and the insulation panel and between the plurality ofinsulation panels.

The front panel may take up an entire front surface of the door, and theinsulation panel may have a smaller area than the front panel, and maybe disposed in an inner area of the front panel. The detection devicemay be disposed at an edge of the front panel.

The display unit may include a display displaying an operation state ofthe refrigerator and an operating button for setting and operating theoperation of the refrigerator. When the door is closed, and when theuser's operation is detected by the detection device, the display andoperating button may be activated.

A door opening device driven by the user's operation and pushing thecabinet to open the door by a predetermined angle may be provided on thedoor, and an operating button which may selectively activate the dooropening device may be provided on the display.

An accommodation member withdrawing device for detecting the opening ofthe door and allowing an accommodation member to be withdrawn may beprovided in the inner side of the cabinet. Moreover, an operating buttonwhich may selectively activate the accommodation member withdrawingdevice may be provided in the display.

A control method of a refrigerator according one implementation mayinclude a step in which a knock detection device that may detect aknocking operation of a user from an outside while the door is closed isactivated, a step of determining whether an input signal of the knockdetection device is valid, and a visualization step in which a lightingunit disposed inside the refrigerator and a display unit disposed insidethe refrigerator and displaying an operation state of the refrigeratorare turned on by a main control part and a state may be determined froman outside of the refrigerator through the panel assembly in the case inwhich the user's operation is determined as valid. The display unit maydisplay the temperature and function of the inside of the refrigeratorwhich is already set in the visualization step.

In the visualization step, the display unit may be controlled to outputa first screen displaying initial temperatures of a refrigeratorcompartment and a freezer compartment, and controlled to output a secondscreen displaying a screen of either the refrigerator compartment orfreezer compartment when a set time is elapsed.

When the door is opened, the display unit may be activated to enableinput of an operating button on the display. When the operating buttonis operated while the door is opened, the display may output a screendisplaying a function, and when the set time is elapsed after the screendisplaying the function is output, a screen displaying the already settemperature of the inside of the refrigerator may be output.

It may be possible to activate or deactivate the setting functionthrough the continuous operation of the operating button, and anactivated or deactivated state may be output through the display.

In some cases, the knock detection device may be mounted on a rearsurface of a panel assembly forming an outer side surface of the doorand it may detect sound when a surface of the panel assembly isvibrated.

A detection device for detecting proximity of the user may be providedon the door, and the main control part may turn on the lighting unit inthe case in which the input signal of the knock detection device isvalid and the detection device detects the proximity of the user at thesame time.

In some implementations, a module PCB that processes the signal of theknock detection device mounted together with the knock detection devicemay be provided on the door. It may be possible to determine theeffectiveness of a knock signal by the module PCB.

In the case in which the knock signal input from the knock detectiondevice is performed a plurality of times within the set time, the modulePCB may determine the knock signal as valid.

When the knock signal is determined as valid from the module PCB, thevalid signal may be transmitted to the control part.

The main control part may be turned off when the set time is elapsedafter the display unit is turned on.

When the valid signal is input from the knock detection device againafter the set time is elapsed after the display unit is turned on, themain control part may turn off the display unit.

The main control part may control the display unit and the lighting unitto be turned on/off together.

Even though all the elements of the implementations are coupled into oneor operated in the combined state, the present disclosure is not limitedto such an implementation. That is, all the elements may be selectivelycombined with each other without departing from the scope of thedisclosure. Furthermore, when it is described that one comprises (orincludes or has) some elements, it should be understood that it maycomprise (or include or have) only those elements, or it may comprise(or include or have) other elements as well as those elements if thereis no specific limitation. Unless otherwise specifically defined herein,all terms comprising technical or scientific terms are to be givenmeanings understood by those skilled in the art. Like terms defined indictionaries, generally used terms needs to be construed as meaning usedin technical contexts and are not construed as ideal or excessivelyformal meanings unless otherwise clearly defined herein.

Although implementations have been described with reference to a numberof illustrative implementations thereof, it will be understood by thoseskilled in the art that various changes in form and details may be madetherein without departing from the spirit and scope of the disclosure asdefined by the appended claims. Therefore, the preferred implementationsshould be considered in a descriptive sense only and not for purposes oflimitation, and also the technical scope of the disclosure is notlimited to the implementations. Furthermore, the present disclosure isdefined not by the detailed description of the disclosure but by theappended claims, and all differences within the scope will be construedas being comprised in the present disclosure.

The present disclosure is directed to a refrigerator which enables atleast a part of a refrigerator door to be selectively transparent by anuser's operation, such that the user may see through an inside of therefrigerator while the refrigerator door is closed, and a control methodthereof.

Also, the present disclosure is directed to a refrigerator in which atleast a part of a front surface of a refrigerator door is formed of halfglass, and a lighting unit in the refrigerator is turned on/off by auser's operation, and thus the user may selectively see through aninside of the refrigerator while the refrigerator door is closed, and acontrol method thereof.

Also, the present disclosure is directed to a refrigerator in which arefrigerator door may be selectively transparent by a knocking operationon a refrigerator door, and thus an inside of the refrigerator becomesvisible, and a control method thereof.

Also, the present disclosure is directed to a refrigerator which is ableto enhance recognition performance and reliability of an operation forselectively enabling an inside of the refrigerator to be visible througha panel assembly while a refrigerator door is closed, and a controlmethod thereof.

Also, the present disclosure is directed to a refrigerator having astructure which is provided at a refrigerator door, enables a use to seethrough an inside of the refrigerator even while the refrigerator dooris closed, and also insulates the refrigerator door.

Also, the present disclosure is directed to a refrigerator which enablesan inside of the refrigerator to be seen through while a lighting unitis turned on by a user's operation, and forms a mirror surface while thelighting unit is turned off, thereby forming an exterior of arefrigerator door.

Also, the present disclosure is directed to a refrigerator which mayselectively visualize a display unit which is selectively transparent byan operation of a user and provided inside the refrigerator and acontrol method thereof.

Also, the present disclosure is directed to a refrigerator in which adisplay unit is provided on an opening part of a main door andconfigured to be shielded by a sub-door to improve the appearance of therefrigerator.

Also, the present disclosure is directed to a refrigerator in which adisplay unit is configured to be selectively detachable inside therefrigerator, so that a suitable display unit may be selectively mountedaccording to functions and models without any structural change.

Also, the present disclosure is directed to a refrigerator which allowsto easily check various states thereof without separately operating adisplay and a control method thereof.

Also, the present disclosure is directed to a refrigerator whichprevents a display unit provided inside the refrigerator from beingabnormally operated due to humidity and moisture of the inside of therefrigerator.

According to an implementation of the present disclosure, there isprovided a refrigerator including a cabinet forming a storage space; amain door opening and closing the storage space and having an openingpart communicated with the storage space formed therein; a sub-doorrotatably mounted on the main door to open and close the opening partand having a panel assembly for selectively viewing an inside of theopening part; a detection device provided in the sub-door and detectinga user's operation; a lighting unit provided inside the refrigerator andturned on according to the operating detection of the detection devicewhen the sub-door is closed to make the panel assembly look transparent;and a display unit provided inside the refrigerator corresponding to thepanel assembly, and being visible when the lighting unit is turned on todisplay an operation state of the refrigerator.

The display unit may be detachably provided in the opening part.

Display installing protrusions may be formed on the opening part, anddisplay guides in which the installing protrusions are inserted may beformed on both side surfaces of the display unit.

The installing protrusions may be provided on both side surfaces of theopening part, and the display guides may be opened downward so that theinstalling protrusions may be inserted and mounted.

A door connector connected to a main control part controlling theoperation of the refrigerator may be provided in the opening part, and adisplay connector electrically connected to the door connector may beprovided on a lower surface of the display.

The display unit may be seated on a lower end of the opening part, andboth side ends of the display may be detachably coupled to an inner sidesurface of the opening part.

The display unit may include an outer case forming an externalappearance and being detachably coupled to the inside of therefrigerator; an inner case seated inside the outer case andaccommodating a display PCB in which a display and an operating buttonare disposed; and a display cover which is in close contact with a frontsurface of the display PCB and shielding an opened front surface of theouter case.

Elements mounted on the out display PCB may be formed to be surroundedby a resin material for moisture proofing.

The display may be exposed to a center of the display cover, and aplurality of operating buttons may be disposed on both left and rightsides of the display.

The display cover may be formed to be inclined rearward toward an upperportion.

A lower end of the display cover may be extended to a positioncorresponding to a rear surface of the sub-door when the sub-door isclosed.

A door switch detecting the opening and closing of the sub-door may beprovided in the main door, and the display unit may be activated andturned on when the sub-door is opened by the door switch.

When the door switch detects that the sub-door is closed after thesub-door is opened, the display unit may be turned off.

The display unit may be turned on/off together with the lighting unit.

Also, a refrigerator according to an implementation of the presentdisclosure includes a door opening and closing a storage space andhaving an opening part communicated with the storage space formedtherein; a panel assembly provided in the opening part and forming anexterior front surface of the door to selectively view an inside of theopening part; a detection device provided in the door and detecting auser's operation; a lighting unit provided inside the refrigerator andturned on according to the operating detection of the detection devicewhile the door is closed, and allowing the panel assembly looktransparent; and a display unit provided inside the refrigeratorcorresponding to the panel assembly and being visible when the lightingunit is turned on to display an operation state of the refrigerator.

The detection device may be a knock detection device which is providedon a rear surface of the panel assembly and detecting a knockingoperation of the panel assembly by the user.

The display unit may include a display displaying an operation state ofthe refrigerator and an operating button for setting and operating theoperation of the refrigerator.

The display and operating button may be activated when the user'soperation is detected by the detection device when the door is closed.

Also, a control method of a refrigerator according to an implementationof the present disclosure including a panel assembly of a half mirrormaterial mounted on an opening part of a door communicated with aninside of the refrigerator so as to selectively view the inside of therefrigerator, the method includes a step in which a knock detectiondevice which may detect a knocking operation of a user from an outsideof the door while the door is closed is activated; a step of determiningwhether an input signal of the knock detection device is valid; and avisualization step in which a lighting unit disposed inside therefrigerator and a display unit disposed inside the refrigerator anddisplaying an operating state of the refrigerator are turned on by amain control part and a status may be confirmed from an outside of therefrigerator through the panel assembly in the case in which the user'soperation is determined as valid.

When the door is opened, the display unit may be activated and an inputof the operating button on the display may be possible.

In certain implementations, a refrigerator may comprise: a cabinet todefine a storage chamber therein; a lighting device configured toilluminate the storage chamber; and a door connected to the cabinet andconfigured to open and close the storage chamber, wherein the doorincludes: a door frame having an opening; a panel assembly configured tocover the opening of the door frame; a display provided at rear of thepanel assembly; a sensor provided in the door frame, and configured todetect an input applied to the panel assembly; and a processorconfigured to control the lighting device and the display according towhether the sensor detects the input, and wherein the door frame and thepanel assembly defines an insulation space which an insulating materialpositioned, an injection port through which a foaming solution isinjected to mold the insulation is formed on a lower side of the doorframe, and the injection port is provided at a position on a lower sideof the door frame which overlaps a space between a lateral side of thepanel assembly and the door frame.

The panel assembly may include: a front panel; an insulating panelprovided rear of the front panel; and a spacer provided between thefront panel and the insulating panel, wherein the front panel and theinsulating panel have a viewing area. The sensor may include amicrophone configured to detect sound waves from the input when theinput is applied to the front panel of the panel assembly. The frontpanel may include a bezel printed along an edge of a rear surface of thefront panel, and the microphone may be provided to face the bezel of thefront panel. The sensor may further include a microphone accommodationhousing which accommodates the microphone, and the microphoneaccommodation housing may be positioned to be in contact with the bezelof the front panel.

The door frame may include a detection device accommodation bracket toreceive the sensor. The door frame may further include an accommodationbracket cover to cover the detection device accommodation part. Thedetection device accommodation bracket may include an opening throughwhich the sensor contacts the front panel when the sensor is received inthe detection device accommodation bracket. An electric wire thatconnects the sensor to the processor may extend along the insulationspace toward a hinge of the door.

In certain implementations, a refrigerator may comprise: a cabinet todefine a storage chamber therein; a lighting device configured toilluminate the storage chamber; a first door connected to the cabinetand configured to open and close the storage chamber and having anopening; a second door configured to open and close the opening of thefirst door and including a panel assembly, the panel assembly includinga front panel, an insulating panel provided a rear of the front panel,and a spacer provided between the front panel and the insulating panel;a display provided at rear of the panel assembly; a sensor positioned tobe in contact with the front panel of the panel assembly, and configuredto detect an input applied to the front panel of the panel assembly; anda processor configured to control the lighting device and the displaybased on whether the sensor detects the input, wherein the second doorfurther includes an insulation space in which an insulating material isreceived, an injection port through which a foaming solution is injectedto mold the insulation is formed on a lower side of the second door, andthe injection port is provided on a lower side of the second door at aposition which overlaps a space corresponding to a lateral side of thepanel assembly.

The sensor may include a microphone configured to detect sound wavesassociated with input when the input is applied to the front panel ofthe panel assembly. The front panel may include a bezel printed along anedge of a rear surface of the front panel, and the sensor may beprovided to face the bezel of the front panel. The sensor may furtherinclude a microphone accommodation housing which accommodates themicrophone, and the microphone accommodation housing may be positionedto be in contact with the bezel of the front panel.

The display may be installed in the first door and provided rear of theinsulation panel when the second door closes the opening. The displaymay be provided in the opening of the first door.

The second door may further include a detection device accommodationbracket to receive the sensor. The detection device accommodationbracket may include an opening through which the sensor contacts thefront panel when the sensor is received in the detection deviceaccommodation bracket. An electric wire that connects the sensor to theprocessor may extend along the insulation space toward a hinge of thesecond door.

In certain implementations, a refrigerator comprises: a cabinet; a doorto open and close the cabinet; and a light provided at one of the dooror the cabinet, wherein the door includes: a door frame having anopening; at least one hinge provided adjacent to a first vertical sidesurface of the door frame; at least one clear panel covering the openingof the door frame; a display provided to be visible through the at leastone clear panel; a sensor provided in the door frame, and configured todetect an input to the door; a processor configured to control at leastone of the light or the display based on the input; and an injectionport through which a foaming solution is received to insulate aninterior of the door frame, wherein the injection port is provided at aposition on a lower side surface to be positioned closer to a secondvertical side surface of the door frame that is opposite to the firstvertical side surface of the door frame.

The door frame may include a bracket having an inner space to receivethe sensor, and wherein the injection port is positioned at an exteriorsurface of the bracket.

It will be understood that when an element or layer is referred to asbeing “on” another element or layer, the element or layer can bedirectly on another element or layer or intervening elements or layers.In contrast, when an element is referred to as being “directly on”another element or layer, there are no intervening elements or layerspresent. As used herein, the term “and/or” includes any and allcombinations of one or more of the associated listed items.

It will be understood that, although the terms first, second, third,etc., may be used herein to describe various elements, components,regions, layers and/or sections, these elements, components, regions,layers and/or sections should not be limited by these terms. These termsare only used to distinguish one element, component, region, layer orsection from another region, layer or section. Thus, a first element,component, region, layer or section could be termed a second element,component, region, layer or section without departing from the teachingsof the present invention.

Spatially relative terms, such as “lower”, “upper” and the like, may beused herein for ease of description to describe the relationship of oneelement or feature to another element(s) or feature(s) as illustrated inthe figures. It will be understood that the spatially relative terms areintended to encompass different orientations of the device in use oroperation, in addition to the orientation depicted in the figures. Forexample, if the device in the figures is turned over, elements describedas “lower” relative to other elements or features would then be oriented“upper” relative to the other elements or features. Thus, the exemplaryterm “lower” can encompass both an orientation of above and below. Thedevice may be otherwise oriented (rotated 90 degrees or at otherorientations) and the spatially relative descriptors used hereininterpreted accordingly.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

Embodiments of the disclosure are described herein with reference tocross-section illustrations that are schematic illustrations ofidealized embodiments (and intermediate structures) of the disclosure.As such, variations from the shapes of the illustrations as a result,for example, of manufacturing techniques and/or tolerances, are to beexpected. Thus, embodiments of the disclosure should not be construed aslimited to the particular shapes of regions illustrated herein but areto include deviations in shapes that result, for example, frommanufacturing.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art andwill not be interpreted in an idealized or overly formal sense unlessexpressly so defined herein.

Any reference in this specification to “one embodiment,” “anembodiment,” “example embodiment,” etc., means that a particularfeature, structure, or characteristic described in connection with theembodiment is included in at least one embodiment of the invention. Theappearances of such phrases in various places in the specification arenot necessarily all referring to the same embodiment. Further, when aparticular feature, structure, or characteristic is described inconnection with any embodiment, it is submitted that it is within thepurview of one skilled in the art to effect such feature, structure, orcharacteristic in connection with other ones of the embodiments.

Although embodiments have been described with reference to a number ofillustrative embodiments thereof, it should be understood that numerousother modifications and embodiments can be devised by those skilled inthe art that will fall within the spirit and scope of the principles ofthis disclosure. More particularly, various variations and modificationsare possible in the component parts and/or arrangements of the subjectcombination arrangement within the scope of the disclosure, the drawingsand the appended claims. In addition to variations and modifications inthe component parts and/or arrangements, alternative uses will also beapparent to those skilled in the art.

What is claimed is:
 1. A refrigerator comprising: a controller; acabinet defining a storage chamber therein; a lighting device providedat the storage chamber and configured to illuminate an interior of thestorage chamber; and a door configured to open and close at least aportion of the storage chamber, the door comprising: a door frame thatat least partially defines an exterior of the door, a door liner coupledto the door frame and defining an opening part, an insulation providedaround the opening part in a space defined between the door frame andthe door liner, a plurality of display installing protrusions providedat opposing inner side surface of the opening part, and a displayassembly mounted in the opening part, wherein the display assemblyincludes: an outer case that defines an interior space, a printedcircuit board (PCB) that is provided in the interior space of the outercase, a plurality of display guides provided at both left and right sidesurface of the outer case, the plurality of display guides beingdetachably coupled to the plurality of the display installingprotrusions, a display that is connected to the PCB and is orientedtoward an outside of the refrigerator, and one or more operating buttonsthat are connected to the PCB and are configured to be operated by auser, and wherein the controller is configured, based on the door beingclosed, to activate the display assembly and the lighting device tothereby allow the user to see the display assembly and the lightingdevice from the outside through the opening part.
 2. The refrigerator ofclaim 1, further comprising a display connection part that is providedat the opening part, wherein the display assembly includes an electricwiring that extends out through the outer case through a connectoropening and connects to the display connection part.
 3. The refrigeratorof claim 1, wherein the one or more operating buttons are configured tobe touched or pushed by the user.
 4. The refrigerator of claim 1,wherein the plurality of display guides are slidably coupled to theplurality of the display installing protrusions.
 5. The refrigerator ofclaim 1, wherein a storage space is provided inside the door, andwherein the display assembly is positioned forward of at least a portionof the storage space.
 6. The refrigerator of claim 5, wherein thedisplay assembly is positioned below at least a portion of the storagespace.
 7. The refrigerator of claim 1, wherein the lighting device isprovided at the cabinet.
 8. The refrigerator of claim 1, wherein thedisplay assembly is tilted rearward relative to a front surface of thedoor.
 9. The refrigerator of claim 1, wherein the display assembly isconfigured to display an operation state of the refrigerator.
 10. Therefrigerator of claim 1, further comprising one or more door basketsthat are provided at the door.
 11. The refrigerator of claim 10, whereinthe display assembly is provided forward of at least one of the one ormore door baskets.
 12. A refrigerator comprising: a cabinet defining astorage chamber therein; a lighting device provided at the storagechamber and configured to illuminate an interior of the storage chamber;and a main door configured to open and close at least a portion of thestorage chamber, the main door comprising: a door frame that at leastpartially defines an exterior of the main door, a door liner coupled tothe door frame and defining an opening part, an insulation providedaround the opening part in a space defined between the door frame andthe door liner, a plurality of display installing protrusions providedat opposing inner side surface of the opening part, and a displayassembly mounted in the opening part, wherein the display assemblyincludes: an outer case that defines an interior space, a printedcircuit board (PCB) that is provided in the interior space of the outercase, a plurality of display guides provided at both left and right sidesurface of the outer case, the plurality of display guides beingdetachably coupled to the plurality of the display installingprotrusions, a display that is connected to the PCB and is orientedtoward an outside of the refrigerator, and one or more operating buttonsthat are connected to the PCB and are configured to be operated by auser, and a sub-door configured to open and close the opening part ofthe main door, the sub-door including a panel assembly that defines afront surface of the sub-door; and a controller configured to controlthe lighting device and the display assembly, wherein the panel assemblyis configured, based on the sub-door being closed, to (i) cover a frontside of the display assembly and the opening part and (ii) allow theuser to see the display assembly and the lighting device from theoutside through the panel assembly.
 13. The refrigerator of claim 12,wherein the one or more operating buttons are configured to be touchedor pushed by the user.
 14. The refrigerator of claim 12, wherein theplurality of display guides are slidably coupled to the plurality of thedisplay installing protrusions.
 15. The refrigerator of claim 12,wherein a storage space is provided inside the main door, and whereinthe display assembly is positioned forward of at least a portion of thestorage space.
 16. The refrigerator of claim 15, wherein the displayassembly is positioned below at least a portion of the storage space.17. The refrigerator of claim 12, wherein the display assembly is tiltedrearward relative to the panel assembly.
 18. The refrigerator of claim12, wherein the display assembly is configured to display an operationstate of the refrigerator.
 19. The refrigerator of claim 12, furthercomprising one or more door baskets that are provided at the main door.20. The refrigerator of claim 19, wherein the display assembly isprovided forward of at least one of the one or more door baskets.